to find a side length of similar triangles, write two equal ratios and set them equal in a proportion. the ratios should be written using the side lengths in each triangle which correspond to each other.
this proportion compares the short side of the largest triangle to its hypotenuse and compares the short side of the smallest triangle to its hypotenuse. to solve for x, cross multiply by multiplying numerator and denominator.
(y - yo) = m.(x - xo)
where (x, y) and (xo, yo) are points of a line and m his slope
if both lines have m equal they are parallels, if they are the opposite inverse they are perpendicular
so, let's see.
line which pass by (-52, -18) and (-29, 53)
(53 - (-18)) = - (-52))
53 + 18 = + 52)
71 = m.(23)
m = 71/23
line which pass by (90, 33) and (19, 56)
(56 - 33) = m.(19 - 90)
23 = )
m = -23/71
as we see, 71/23 and -23/71 are opposite inverses of one another, so they are perpendicular lines.
answer: the answer is c) $0.85
if he has 3/20 of a dollar that calculates to $0.15 and $1.00 minus $0.15 equals $0.85