Question

Use the stated variant of the Law of Cosines, a2=b2+c2−2bc⋅cosA
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, 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=

Answer 1

Use 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° (to the nearest whole number).