Answer:
1=15.7
2:31.4
3:12.5
Step-by-step explanation:
1=5×3.14=15.71
2:5×2=10×3.14=31.42
3:39.25÷3.14=12.5
hope this helps
First of all, you should know/notice that

You should also know how negative exponents work:

So, if you wanted

the answer would be x=3, but since you want 125 to be at the denominator, the answer is x=-3:

Step-by-step explanation:
lets radius be r and height be h,
r+h=21 -----(1)
curved surface area
2×pi×r×h=616 -----(2)
use simultaneous eqn to solve for r and h.
total surface area of cylinder= 2×pi×r×h + 2×pi×r²
= ans if im not wrong
area of a triangle = 1/2 base x height
56.4 = 1/2 x 12 x height
56.4 = 6 x height
height = 56.4 /6 = 9.4cm