7π/12 lies in the second quadrant, so we expect cos(7π/12) to be negative.
Recall that
which tells us
Now,
and so
Answer:
4 ÷ 5 = 2/5
5 ÷ 4 = 1 1/4
12 ÷ 30 = 2/5
30 ÷ 12 = 2 1/2
The other dimension of the sandbox must be (4x+3).
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