Question

Use the stated variant of the Law of Cosines, a2=b2+c2−2bc⋅cosA
, to find the value of angle A
in a right triangle, where a=8
, b=15
, and c=17
. Round your answer to the nearest whole number.(1 point)
A=
degrees
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Answer 1

Using the law of cosines:
cos A = (b^2 + c^2 − a^2) / (2bc) = (225 + 289 − 64) / (2·15·17) = 450/510 = 15/17.

So A = arccos(15/17) ≈ 28.07°, rounded to the nearest degree: 28°.

A = 28 degrees