Given: costheta=3/5 and sintheta=4/5
Find the value of sin2theta

Please explain.​

Two cyclists 84 miles apart start riding toward each other at the samen time. one cycles 2 times as fast as the other. if they meet 4 hours later what is the speed (in miles) of the faster cyclists

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?