Question

Find fRound the answer to the nearest tenth.

A. 54.5°
B. 57.2°
C. 90.0°
D. 109.2°

Answer 1

109.2 degrees

Explanation:

Use the cos law to find angle F

3.1^2 = 2^2 + 1.8^2 - 2 (2)(1.8) cos F

shows cos f = -.329

arc cos( - .329) = angle F =109.2 degrees

Answer 2

D. 109.2
A triangle equals 180° and angle F is an obtuse angle therefore it can’t be 90° or lower.
180° - 109.2° = 70.8°
The smaller angles would each equal 35.4°