2. if the diameter of a circle changes from 5 cm to 15 cm, how will the circumference change? a. multiplies by 1/3 b. multiplies by 3 c. increases by 10 d. decreases by 10 5. given a circle with a circumference of 33 cm, find the radius. a. 3.24 b. 5.25 c. 6.48 d. 10.50 8. a circle has an area of 36 inches squared. what is the area of a sector of the circle that had a central angle of 30 degrees? show all work!with the above questions(also there is one attached).

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?