Let
x-------------> amount added <span>to each side
</span>A-------------> area increased----------> 84 ft²
we know that
A=(10+x)*(5+x)=84-----------> 10*5+10*x+5*x+x²
50+15x+x²=84----------> x²+15x-34=0
<span>solving the second order equation
</span>x1=-17
x2=2
the answer is x=2 ft
Are you sure your in high school, also it's answer #3.
A pentagon gas 5 sides. Therefore multiply the length of one side by 5.
921x5=4605 feet
Tan 34 = 12/x and then uhm, put 12/tan34 into ur calculator