Explain how to find the value of x. Be sure to include the postulates, definitions and theorems that justify your answer. Can someone help me asap

x = 12

Step-by-step explanation:

We can see two triangles rectangles, we will use the angle S to solve this, as this angle is common to both triangles.

We know that:

cos(S) = adj cathetus/hipotenuse.

Then we have, for the triangle SRT.

Cos(S) = 9/SR.

for the big triangle, SQR, we have:

Cos(S) = SR/(9 + 16)

now we can find the quotient of those two equations and get:

cos(S)/cos(S) = 9/Sr*(9+16)/SR

SR^2 = 9*(25)

SR =  15.

Now with this side we can find the value of x.

We can use the Pythagorean theorem in the triangle SRT, where the sum of the squared cathetus is equal to the hypotenuse:

9^2 + x^2 = 15^2

x = √(15^2  - 9^2) = 12

the surface area is 124cm²

step-by-step explanation:

length: 4cm

width: 9cm

height:   2cm