answer : 3
step by step:
this may seem hard but it is easy.
the first thing to do is to look at the bottom of the shape it shows a right triangle that is missing the hypotenuse lets see how to solve for that:
name the hypotenuse x
then write the equation
x^2= 6^2 + 6^2
x^2= 72
take both the square root of them
x = 8.5
next part is the rectangle and we see that it has been split into 2 right triangles which are the same but the cool part is that if we solve for one of the triangles we solve for the other we are going to do the same steps again notice now we are solving for the right angle that's not labeled if we solve that then that means we solve for the other triangle that is labelled x
first off we know that the hypotenuse is 9 and one angle is 8.5 so here is the equation:
x^2 = 9^2 - 8.5^2
x^2 = 8.75
take square root of both
x = 3