Ask Question
10 August, 19:17

A triangle has sides of length 7 cm, 12 cm, and 15 cm. What is the measure of the angle opposite the side that is 7 cm long? Round to the nearest degree. 27° 42° 63° 77°

+5
Answers (1)
  1. 10 August, 22:58
    0
    Answer:Given : A triangle has sides of length 7 cm, 12 cm, and 15 cm.

    To find : Angle opposite the side that is 7 cm long? Round to the nearest degree.

    Solution : We have a triangle of sides a=7 cm, b = 12 cm, c=15 cm.

    By using cosine rule : a² = b²+c² - 2 bc cos (A).

    Where angle A is opposite to side a=7 cm.

    Plugging the values in formula,

    (7) ² = (12) ² + (15) ² - 2 (12) (15) cos (A).

    49 = 144 + 225 - 360 cos (A).

    49 = 369 - 360 cos (A).

    -320 = - 360 cos (A).

    On dividing by - 360 and switching side

    A = cos^{-1} (0.89) = 27 / degrees.

    Therefore, angle opposite the side that is 7 cm is 27 degrees.
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “A triangle has sides of length 7 cm, 12 cm, and 15 cm. What is the measure of the angle opposite the side that is 7 cm long? Round to the ...” in 📙 Mathematics if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers