1. The shape of cross-section is a circle.
2. The face parallel to ABCD is EFGH. Since this is a a rectangular shape,
A = L*H = 12*6 = 72 cm^2
3. The cross-section parallel to ABC is DEF with h = 12 ft, b= 5ft (where h is the height and b is the base of a right angled triangle).
Area, A = 1/2 *b*h = 1/2*5*12 =30 ft^2
4. Plane BDHF is a rectangle shape whose length is the diagonal of ABCD.
Diagonal BD = sqrt (AB^2+BD^2) = sqrt (8^2+7^2) = 10.63 cm.
Perimeter, P = 2(BD+DH) = 2(10.63+6) = 33.26 cm
Well if you multiply 66.7 x 100 you get 6,670.0. When multiplying by numbers like 10, 100, 1,000, etc, just simply transfer the 0's. So in this case, there are 2 0's in 100, so you add 2 of the 0's behind 66.7. So when you add the 2 of the 0's you get 6,670.0 which should be your answer.
12 is the answer your looking for
The correct answer is 32 because:
x-14 = 18 => add 14 to both sides=>
x=32