I need help with 6 and 8

A spherical party balloon is being inflated with helium pumped in at a rate of 7 cubic feet per minute. How fast is the radius growing at the instant when the radius has reached 1 ft? HINT [See Example 1.] (The volume of a sphere of radius r is V = mrs. Round your answer to two decimal places.) * ft/min Need Help? Read It 7. [8.07/7.69 Points] DETAILS PREVIOUS ANSWERS WANEFMAC7 12.5.012. MY NOTES PRACTICE ANOTHER A rather flimsy spherical balloon is designed to pop at the instant its radius has reached 6 centimeters. Assuming the balloon is filled with helium at a rate of 11 cubic centimeters per second, calculate how fast the radius is growing at the instant it pops. (The volume of a sphere of radius r is V = /. Round your answer to two decimal places.) 0.02 cm/s Need Help? Read It Watch It 8. [-/7.69 Points] DETAILS WANEFMAC7 12.5.015. MY NOTES PRACTICE ANOTHER The base of a 45-foot ladder is being pulled away from a wall at a rate of 13 feet per second. How fast is the top of the ladder sliding down the wall at the instant when the base of the ladder is 27 feet from the wall? HINT [See Example 2.] ft /s Need Help? Read It