In ΔABC, a = 2, b = 3, and c = 4. Find the value of cosC. Is the triangle acute, right, or obtuse?

Question

Jasiah Garner

Mathematics

25 February, 18:27

In ΔABC, a = 2, b = 3, and c = 4. Find the value of cosC. Is the triangle acute, right, or obtuse?

+3

Answers (2)

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Bennett Cox · Answer 1

The applicable formula is known as the law of cosines

C² = a² + b² - 2abcosC

cosC = (a² + b² - c²) / 2ab

= (2² + 3² - 4²) / 2*2*3

= (13-16) / 12

= - 3/12

= - 1/4

Tamara · Answer 2

4^2 = 3^2 + 2^2 - 2 * 3 * 2 * cosC 16 = 13 - 12 * cosC 12 * cosC = - 3 cosC = - 1/4.