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hobo_ken
Nov5-04, 10:33 PM
Hi, I'm having trouble with this one problem. I've been struggling to do it for hours! Ok maybe mins, but I still can't get the right answer. :frown:

The altitude of a triangle is increasing at a rate of 3 centimeters/minute while the area of the triangle is increasing at a rate of 3.5 square centimeters/minute. At what rate is the base of the triangle changing when the altitude is 9.5 centimeters and the area is 99 square centimeters?

The answer I got was 7/3.

mathman
Nov6-04, 04:05 PM
A=area, b=base, h=altitude.

b=2A/h. Therefore b'=2(hA'-Ah')/h2.

You do the arithmetic. (I did not get 7/3).