Diagonal length of a square is growing at a rate of 20 meters per second. How fast is the are enclosed by the square growing at the instants the area equals 100 squared meters? Walk through please!.

Question

Diagonal length of a square is growing at a rate of 20 meters per second. How fast is the are enclosed by the square growing at the instants the area equals 100 squared meters? Walk through please!>.<

anonymous · Answer

related rate problem?

anonymous · Answer

area of a square with diagonal $x$ is $$A(x)=\frac{d^2}{2}$$ is a start

anonymous · Answer

i mean 
$$A(x)=\frac{x^2}{2}$$

anonymous · Answer

then take the derivative, get 
$$A'=xx'$$

anonymous · Answer

you are told $x'=20$ so this gives 
$$A'=20x$$ then if $x=100$ you can find $A'$

anonymous · Answer

hope it is more or less clear

anonymous · Answer

After a few tries I got it thanks(: