Question

In ΔEFG, e = 2.6 cm, f = 7.2 cm and g=8.3 cm. Find the measure of ∠F to the nearest degree.

{}Urgen{} Delta Math

Answer 1

57

Explanation:

cos F = (e² + g² - f²)/2eg

cos F = (2.6² + 8.3²- 7.2²)/2(2.6)(8.3)

= 0.5516

∠F = arccos 0.5516

∠F = 57° (rounded to the nearest degree)

Answer 2

• 57°

Explanation:

Use the law of cosines:

• cos F = (e² + g² - f²)/2eg
• cos F = (2.6² + 8.3²- 7.2²)/2(2.6)(8.3)
• = 0.5516
• ∠F = arccos 0.5516
• ∠F = 57° (rounded to the nearest degree)