SOLUTION: The measures of the sides of an isosceles triangle are 10, 10, and 4. Find the measure of a base angle to the nearest degree.
a. 23
b. 60
c. 78
d. 85
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-> SOLUTION: The measures of the sides of an isosceles triangle are 10, 10, and 4. Find the measure of a base angle to the nearest degree.
a. 23
b. 60
c. 78
d. 85
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Question 281782: The measures of the sides of an isosceles triangle are 10, 10, and 4. Find the measure of a base angle to the nearest degree.
a. 23
b. 60
c. 78
d. 85 Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! The measures of the sides of an isosceles triangle are 10, 10, and 4. Find the measure of a base angle to the nearest degree.
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Use Law of Cosines:
cos(A) = (b^2 + c^2 - a^2)/2bc
Find the angle opposite 4:
cos(A) = (10^2 + 10^2-4^2)/(2*10*10)
cos(A) = (84)/200 = 0.42
cos^-1(0.42) = 65 degrees
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Each base angle = (180-65)/2 = 57.5 degrees
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Cheers,
Stan H.
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