Answer:
the answer is C
Step-by-step explanation:
Answer:
C. 468mm²
Step-by-step explanation:
The formula for the surface area of rectangular prism is:
Let's break down our variables.
L = 12mm
W = 6mm
H = 7mm + 2mm = 9mm
Now we substitute our values in the formula:
-- 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 !
