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#### xyz_1965

##### Member

- Jul 26, 2020

- 81

Solution:

I think dropping a perpendicular line from the vertex at C gives me two congruent triangles.

cos(A) = cos(B) = 2/8 = 1/4.

arccos(1/4) = 75.5 degrees

So, angle A = angle B = 75.5 degrees, rounded to nearest one decimal place.

Angle C = 180 - 2arccos(1/4) = 29 degrees, rounded to nearest one decimal place.

I can do the same calculations in radians:

arccos(1/4) = 0.97 radians

So, angle A = angle B = 1.32 radians, rounded to two decimal places.

Angle C = pi - 2arccos(1/4) = 0.51 radians, rounded to two decimal places.

I hope to be right. The answers are not given in the back of the book for even number questions.