Question 109857
Hello!

The formula for the area of a trapezoid is {{{A=(b1+b2)/2*h}}}, we know b1 and the height but the problem is we don't know the base2. We can represent b2 as variable x. We know that the area is 186. so the new formula is {{{186=(21+x)/2*11}}}. First let's distribute 11, if we do that it will be {{{186=(231+11x)/2}}}. Then we multiply both sides by 2 so there is no fraction, it will be like this {{{372=231+11x}}} we got 372 because we multiply 186 by 2, we got 231+11x because we multiply 231+11x/2 by 2. Is that clear? Now, we got this equation {{{372=231+11x}}} let's subtract 231 from 372 and 231+11x. We will get {{{141=11x}}} divide both sides by 11. You will get {{{12.82=x}}}. So the final answer is 12.82in.



I hoped you understand my solution!