We are given a design of a stained glass window. We want to know what kind of figure â–³ AOC is.
Note that both AO and CO are radii of the circle. Therefore, they have the same length. Also, we can see that ∠AOC is a quarter of a complete angle, so its measure is 90^(∘).
1/4 * 360^(∘) = 90^(∘)
Let's take a closer look at the triangle.
Two of the sides of the triangle are congruent, so the triangle is an isosceles triangle. Since one of the angles in the triangle is a right angle, it is a right triangle. A right triangle cannot be an equilateral triangle, since the measure of every angle in an equilateral triangle is 60^(∘). To sum up, △ AOC is an isosceles right triangle.
