Answer:

or

Step-by-step explanation:
FOIL
(1/2)h*B1+ (1/2)h*B2=A
subtract the B2 term
(1/2)h*B1 = A- (1/2)h*B2
multiply by 2
h*B1 = 2A - h*B2
divide by h

or

Answer:
The length of arc is 7.85cm
Step-by-step explanation:
You can find the length of arc by using the formula :

θ = 90°
r = 5cm
Arc = (90/360)×2×π×5
= (1/4)×2×π×5
= (1/4)×10×π
= (5/2)π
= 7.85 cm (3s.f)
Answer:
surface area of rectangular prisms A=2(wl+hl+hw)
surface area of cubes A=
Step-by-step explanation: