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jdiel14
17.04.2020 •
Mathematics
A manufacturer claims that the mean lifetime of its drill is 1000 hours. A homeowner selects 25 drills and finds the mean lifetime to be 980 hours with a sample standard deviation of 80 hours. If = 0.05, test the manufacturer's claim.
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Ответ:
Step-by-step explanation:
This is because we know that angle B is 120° also, and cointerior angles add to 180°, which makes angle BCF 60°. Then we can divide this by 2 as angle BCF is bisected by AC, so therefore angle ACF is 30° as 60 ÷ 2 = 30. You can then prove angle A is 90°.