pg 99 Q13

**sand is poured into a heap in the shape of a right circular cone whose height is always equal to the radius of the base, at a constant rate of 4 cm^3/min. when the heap is 10 cm high, how fast is the height increasing,**

**and the area of the base increasing.**

**i keep getting the wrong answer: its supposed to be 1/25pi cm/min and for second part 0.8 cm^2/ min**

thanks help will be appreciated