Answer:
B. y=0
Step-by-step explanation:
Answer:

Step-by-step explanation:
We have:
(1) two trapezoids with bases b₁ = 7cm and b₂ = 5cm and the height h = 4cm
(2) three rectangles 3 cm × 7 cm, 3 cm × 4 cm and 3 cm × 5 cm.
The formula of an area of a trapezoid:

Substitute:

Calculate the areas of the rectangles:

The Surface Area:

Answer:
see explanation
Step-by-step explanation:
using the identity
cos2a = 2cos²a - 1 , then
cos2a
= 2[
(a +
) ]² - 1
= 2 [
(a² +
+ 2) ] - 1
=
(a² +
) + 1 - 1
=
(a² +
) ← thus verified
Answer:
I think it is 300.
Step-by-step explanation: