check the picture below.
so, when we have a line from a 90° angle running perpendicular to the opposite side, like in this case, we end up with three similar triangles, a large one containing the other two, a medium and a small one.
now, using the sides proportions as you see there, of the small and large one, we get that much.
You would equal the equations together then solve for a variable.
-4x - 3 = -2x + 1
-4x + 2x = 1 + 3
-2x = 4
—— —-
-2 -2
x = -2
then take that x value and substitute it into any one of the equations.
Equation #1
y = -4(-2) -3
= 8 - 3
= 5
Equation #2
y = -2(-2) + 1
= 4 + 1
= 5
-- You have two angles.
-- They're complementary . . . they add up to 90 degrees.
-- One is 4 times as big as the other one.
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-- The smaller angle has 1 share of the 90 degrees.
-- The bigger angle has 4 shares of the 90 degrees.
-- (The smaller one is 1/4 the size of the bigger one.
The bigger one is 4 times the size of the smaller one.)
-- When you add them together, you get 5 shares, totaling 90 degrees.
-- What's the size of each share ? It's 90/5 = 18 degrees.
-- The smaller angle gets one share . . . 18 degrees.
-- The bigger angle gets 4 shares. (4 x 18) = 72 degrees.
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Check:
-- Is the small one 1/4 the size of the big one ? 18/72 = 1/4 Yes.
-- Are they complementary ? Do they add up to 90 degrees ?
18 + 72 = 90 Yes.
yay !
