asked 17.1k views
2 votes
In △ABC, AB=7, BC=8,
and AC=9.
What is m∠C
to the nearest degree?

In △ABC, AB=7, BC=8, and AC=9. What is m∠C to the nearest degree?-example-1
asked
User Phylae
by
7.8k points

2 Answers

6 votes

To find the measure of angle C in triangle ABC, we can use the Law of Cosines, which states that for any triangle with sides a, b, and c and opposite angles A, B, and C:c^2 = a^2 + b^2 - 2abcos(C)In this case, we know that AB = 7, BC = 8, and AC = 9. Plugging these values into the Law of Cosines equation and solving for cos(C), we get:cos(C) = (7^2 + 9^2 - 8^2) / (2 * 7 * 9)

cos(C) = 0.6111111Taking the inverse cosine (cos^-1) of 0.6111111, we get the angle C:C = cos^-1(0.6111111)

C ≈ 51.96 degreesTherefore, to the nearest degree, m∠C ≈ 52 degrees.

answered
User WebWanderer
by
8.0k points
7 votes

Answer:

48°

Explanation:

Use the Law of Cosines.

c² = a² + b² - 2ab cos C

7² = 8² + 9² - 2(8)(9) × cos C

49 = 145 - 144 cos C

-144 cos C = -96

cos C = 2/3

C = 48.196...°

Answer: 48°

answered
User John Boe
by
8.5k points
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