3 years ago

PLEASE HELP!!! b=7,c=10, COS A = 40°, a=____

Mathematics

1 answer:

Reptile [31]3 years ago

7 0

Step-by-step explanation:

According to the cosine rule :

a = b² + c² - 2bc × cosA

a = 7² + 10² - 2 × 7 × 10 × cos40⁰

a = 49 + 100 - 106.4

a = 149 - 106.4

a = 43.4

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