Question 107334
Find the area of a rectangle with length 4 and diagonal 5. 
You need to start by finding the width of the rectangle, you do that by the Pythagorean theorem. One leg = 4, hypotenuse=5;
{{{a^2+b^2=c^2}}}
{{{4^2+b^2=5^2}}}
{{{4^2-5^2=b^2}}}
{{{sqrt(16-25)=sqrt(b)}}}
{{{b=sqrt(9)}}} so the width would be 3;
Now we can find the area;
A=LW
A=4(3)
A=12
:)