Find m A. 20
B. 16
C. 17
D. 18

Choice C) 17 degrees

Work Shown:

Apply the law of cosines

c^2 = a^2 + b^2 - 2*a*b*cos(C)

12^2 = 28^2 + 18^2 - 2*28*18*cos(C)

144 = 1108 - 1008cos(C)

144+1008cos(C) = 1108

1008cos(C) = 1108-144

1008cos(C) = 964

cos(C) = 964/1008

C = arccos(964/1008)

C = 16.991286936969 which is approximate

C = 17 degrees

Note: arccos is the same as inverse cosine.

the final amount you will pay is $68.04.

the tip is determined by the pre-tax amount, so we calculate the tip based on the original bill, not after we've added sales tax.

to find the tip:

we can divide 54.00 by 100 to get 1% of 54. then we multiply that by 18.

54 / 100 = .54

.54 x 18 = 9.72

tip = 9.72$

to find the tax:

we can divide 54.00 by 100 to get 1% of 54. then we can multiply that by 8 to get 8%.

54 / 100 = .54

.54 x 8 = 4.32

tax= 4.32

now we can add the tip and tax to the bill to get our total.

54 + 9.72 + 4.32 = 68.04

total: $68.04

step-by-step explanation: