Evaluate sec 240Á without using a calculator by using ratios in a reference triangle.
2 answers:
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Answer:
b = 90
Step-by-step explanation:
Sum the interior angles of the pentagon and equate to 540
Starting from the top and going clockwise
b + b + 45 + 90 + 2b - 90 + b = 540 ← simplify left side
b + 45 = 540 ( multiply through by 2 to clear the fraction )
11b + 90 = 1080 ( subtract 90 from both sides )
11b = 990 ( divide both sides by 11 )
b = 90
Thus
b + 45 = 90 + 45 = 135
2b - 90 = 2(90) - 90 = 180 - 90 = 90
b =
× 90 = 135
The angle measure from the top clockwise are
90°, 135°, 90°, 90°, 135°