Trig law of cosines

determine the approximate measure of angle c.

90.0 degrees

95.7 degrees

60.9 degrees

102.3 degrees

C ≈ 95.7°

Step-by-step explanation:

Law of cosines:

c² = a² + b² − 2ab cos C

where a, b, and c are the sides of the triangle, and C is the angle opposite of side c.

9² = 5² + 7² − 2(5)(7) cos C

81 = 25 + 49 − 70 cos C

81 = 25 + 49 − 70 cos C

7 = -70 cos C

-1/10 = cos C

C ≈ 95.7°

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation: