Answer:
8. 8.80
9. 90
Step-by-step explanation:
Question 8: Use the Pythagorean formula
DE² = DF²+EF²
EF² = DE² - DF²
= 16.2² - 13.6²
= 77.48
EF = √77.48 = 8.80 (Answer)
Question 9: Use the Cosine Rule
GI² = GH² +HI² - 2·GH·HI·Cos ∠GHI
= 60² + 42² - 2·60·42·Cos 123
= 3600 +1764 - (-2744.98)
= 8108.98
GI = √8108.98 = 90
Eq. 1 .10x + .25y = 9.45
Eq. 2 x + y = 60 rewrite as x = 60 - y and substitute into equation 1.
.10(60 - y) + .25y = 9.45
6 - .1y + .25y = 9.45
6 + .15y = 9.45
.15y = 3.45
y = 23
60 - 23 = 37
23 quarters
37 dimes
23* .25 = 5.75
37 * .1 = 3.70
5.75 + 3.70 =9.45
Third angle = 180 - (44 + 72) = 180 - 116 = 64 degrees answer
