-10 = -5/4v
First multiply 4v on both sides leaving you with the following equation:
-10(4v) = -5
Simplify it.
-40v = -5
Divide -40 on both sides to solve for v.
v = -5/-40
Reduce the fraction down to simplest terms.
v = 1/8
Gosh that looks hard. but i wish you the best of luck on it
If C=2pi times r, then r=C divided by 2pi, just use your calculator, punch in 53.4 ÷ 2 ÷3.14, the answer should be 8.5