Lisa needs to get her roof re-done The roofing company charges a $500 flat fee They also charge $1.25 per square foot of the roo
2 answers:
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Answer:
A. 17
Step-by-step explanation:
using the cosine rule (also see attached for reference):
AB² = BC² + AC² - 2·AC·BC cos C
2·AC·BC cos C = BC² + AC² - AB²
Given that AC = 18, AB = 12 and BC = 18, substituting these into the formula
2(18)(28) cos C = 28² + 18² - 12²
1008 cos C = 964
cos C = 964/1008
cos C = 0.9563
C = cos⁻¹ 0.9563
C = 16.99 ( = 17° rounded to nearest degree)
