Geometry is a vast subject entailing various subtopics like squares, rectangles, etc. One of them which tends to confuse students is triangles. This is because, unlike squares and rectangles, which present themselves as just one type, triangles are segregated into different types. Based on the sides, we have equilateral triangles, scalene triangles, and isosceles triangles. And based on angles, we have the acute, obtuse, and right triangles. All these variations can totally confuse students, we agree. One way to make things a little easy for learners is to do a simple types of triangles craft and the second is to merge these concepts with some real-life examples.
Real-life examples show us how the things we learn at school display their presence and application in the little things that surround us. While it’s easier to appreciate the use of concepts we learn in science and geography in daily life, it is not the same with math. Geometrical concepts like triangles are difficult to understand in the context of the real world. To support our curious learners, we have come up with this article where we will mention some of the most common real-life examples of the isosceles triangle, the triangle with two equal sides.
How is an isosceles triangle different from other triangles?
Like other triangles, the isosceles triangle is also a three-sided closed polygon. What sets it apart from other triangles is that it has two sides of the same length. The two same-length sides are called the “legs” of the triangle, and the third unequal side is known as its “base.” A few other properties of an isosceles triangle are:
1. An isosceles triangle has two equal base angles as the two angles opposite to the equal sides are congruent.
2. The third angle, known as the apex angle, is not equal to the two base angles.
3. A line drawn straight from the apex to the base splits the base into two equal parts.
4. The apex angle can either be an acute angle or an obtuse angle.
5. The sum of all sides of an isosceles triangle gives its perimeter.
6. The sum of all angles of an isosceles triangle is 180 degrees.
Spotting isosceles triangles around us: 10 real-world examples
1. A slice of pizza
Who doesn’t love a slice (or more!) of pizza for dinner? This mouth-watering circular delicacy is traditionally divided into triangular portions before serving so that it’s easy to eat and share. The next time you eat pizza, observe carefully, and you will notice that each slice resembles an isosceles triangle. Yes, we know its base isn’t a straight line, but its overall shape is similar to an isosceles triangle with two sides of the same size.
2. A pair of earrings
Contemporary style earrings are so fashionable. Some of them are designed in geometrical shapes like squares, circles, and even triangles! A jewelry section in a store will probably showcase a few triangular earrings as well. The ones with two long equal sides and a small base will look just like isosceles triangles. Who knew geometrical shapes could find a place in jewelry design and work so well in enhancing a person’s personality?
3. Church spire
Many churches have this beautiful architectural feature on the top known as the steeple. The steeple gives a long look to the buildings. The topmost part of the steeple is called the spire, and this is what looks like an isosceles triangle. When you look at this tall conical shape, it appears as a triangle with two long sides and a comparatively smaller base. A spire has a religious symbolism and is very common in Gothic architecture.
4. Tepee
Tepee or tipi is a type of tent made by North American Indians residing in the Great Lakes regions and the Plains. These conical-shaped tents are constructed by tying poles together at the top and spreading them at the bottom to form a conical shape. This structure is then covered with animal skins or canvas to turn it into a comfortable living space. The tepee is an excellent example of an isosceles triangle, as the adjacent poles of the tepee form quite a few of them with the base.
5. A flying flock of birds
Ever noticed how a flock of birds, especially the migratory ones, fly from one place to the other? They form a classic V-shape during their flight. While we are not here to discuss why they prefer this form of movement, we have surely noticed that this V-shape does resemble an isosceles triangle if we draw an imaginary line over it. The two lanes of birds form the equal sides of the triangle with a fictional base of shorter or longer length.
6. Tripod stand
Spread the legs of a tripod stand and see how it looks. Do you see anything familiar? Yes, the adjacent legs of a tripod also make an isosceles triangle. Some tripods come with foldable legs. You can stretch them to open up and increase the height of the tripod. No matter what height you choose, you will always observe three isosceles triangles forming in the tripod.
7. Truss bridge
A bridge with a truss, a superstructure that bears the load, is also a great example of a real-world isosceles triangle. A truss bridge has not just one but several triangular units. The metal triangles form a durable structure that can bear large amounts of loads. Truss bridges are commonly used to build railroad and military bridges because they need less material for construction and can support a considerable amount of weight on it.
8. A Rooftop
Look at the rooftop of houses. Don’t you think these slanting structures also look like isosceles triangles? If not, see again! A rooftop has two slanting sides of equal lengths, and the sides are connected to each other at the base of a different length. Since houses come in varied sizes, the rooftops, or if we may say, the isosceles triangles, also vary in size.
9. Hangers
Hangers are a very common household item, and guess what! It also resembles an isosceles triangle. Don’t believe us? Pick a hanger out of the closet and use a ruler to check its dimensions. You will see that the two sides of the hanger and its base follow the basic properties of the triangle in discussion. At the store, you may find steel, plastic, or wood hangers. They may even differ in size. But they all hold the shape of an isosceles triangle.
10. Arrowheads
A bow and an arrow were powerful weapons used in ancient times for self-defense and hunting. Arrows used in them were made of a wooden shaft that had a feathered tail at one end. On the other end was an arrowhead made of materials like metal and stone so it could be sharp enough to serve its purpose. Interestingly, a classic arrowhead was also designed in the shape of an isosceles triangle. Arrowsmiths preferred this shape because it had a pointy apex with a strong base, capable of creating a solid impact and penetrating deep into the target.
Concluding thoughts
Though not as common as an equilateral triangle, isosceles triangles are also a commonly found shape in the real world. Once students know the difference between this triangle with two equal sides and other triangles, it gets easier for them to spot it in their surroundings. Real-world examples like those of the isosceles triangle, right angle triangle, and others help build a connection between what students are learning and what they see outside the classroom. This connection fosters critical thinking and engages students much better. So, use these examples as a teaching strategy to see how they spark interest in the classroom and make learning more meaningful for your students.
I am Priyanka Sonkushre, a writer and blogger. I am the person behind “One Loving Mama,” a mom blog. Equipped with a Bachelor’s degree along with an MBA, my healthcare background helps me deeply understand learning difficulties. I know how challenging it can be for parents to find the right resources to help their children excel in life. So, here I am to blend my healthcare expertise with my parenting experience to create valuable and helpful resources for parents and teachers supporting children with learning differences. If you wish, you can follow me on Facebook and LinkedIn.