I have to solve for x

Dr. cooper just started an experiment. he will collect data for 8 days. how many hours is this

Which of the following is the equation that says that the product of a number and ten is equal to 20 percent of that number ? a) 10n= 2.0n b) 10+n=.20n c) n+ .20n=10 d) 10n=0.20n

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.