### Home > CCG > Chapter Ch7 > Lesson 7.2.3 > Problem 7-78

7-78.

Tromika wants to find the area of the isosceles triangle below.

She decided to start by drawing a height from vertex to sideas shown at right. Will the two smaller triangles be congruent? In other words, is? Why or why not?

Look at the two triangles that are created. They share a side, and the tick marks mean the side lengths are equal. Are the triangles congruent?

Yes, they are congruent by

. What is

??since congruent triangles have congruent parts. Find

. Show how you got your answer.Which trig ratio can you use to determine this length?

Find the area of

. How do you find the area of a triangle? Do you have enough information to calculate the area?