VOLUME OF A TUMOR The shape of a cancerous tumor is roughly spherical and has volumewhere...

VOLUME OF A TUMOR The shape of a cancerous tumor is roughly spherical and has volume

where r is the radius in centimeters.

a. When first observed, the tumor has radius 0.73 cm, and 45 days later, the radius is 0.95 cm. By how much does the volume of the tumor increase during this period?

b. After being treated with chemotherapy, the radius of the tumor decreases by 23%. What is the corresponding percentage decrease in the volume of the tumor?