I need help on this one please help me

Answer:
Step-by-step explanation:
Between the two diagrams, you have an isosceles triangle
The base is 26 on the triangle on the right, and 20 on the left triangle.
So that's the ratio used to create the proportion
26/20 = x/26 cross multiply
20x = 26 * 26
20x = 676 Divide by 20
x = 676 / 20
x = 33.8