Using formula: <span>A=Pi*r^2
A would represent the area of the whole mural but we would plug in r as 25, 50 is the whole width half of it is 25 which is the radius. the whole circle has a degree of 360 but we need the area of 38 degree.</span><span>
A=38/360*pi*25^2
=16.57</span>
It's a little hard to tell without more information as to what you are learning, but could it be the Golden Ratio? I believe it might have been discovered in ancient Greece...
{(3x)}^{2}-2(3x)(5)+{5}^{2}
−2(3x)(5)+5
2
{(3x-5)}^{2}
39
Divide 78 by 2 to get 39 and add in to the number
