>>the altitude (height h) of a triangle is increasing 
at a rate of 1 cm/min<< 



>>while the area A of the triangle is increasing at a 
rate of 2cm^2 /min.<< 



>>at what rate is the base of the triangle changing...<<



 

Substitute  and 



Multiply both side by 2





We will need b and h to solve for .

>>when the altitude (height h) is 10cm and the area is 100cm^2?<<

We go back to the area formula:






Substitute  and  in







The negative sign means the base is DEcreasing
at the rate of -1.6 cm/min at that instant.

Edwin