SOLUTION: What is the acute angle at the point of intersection of two lines y=-0.4x+10 and y = 3x-5?

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Question 1078456: What is the acute angle at the point of intersection of two lines y=-0.4x+10 and y = 3x-5?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
What is the acute angle at the point of intersection of two lines y=-0.4x+10 and y = 3x-5?
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Graph::
graph%28400%2C400%2C-5%2C30%2C-10%2C10%2C-0.4x%2B10%2C3x-5%29
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Notice the triangle made by the lines.
base angle where y = 3x-5 crosses the x-axis = tan^-1(3) = 71.56 degrees
base angle where y = -0.4x+10 crosses the x-axis = -tan^-1(-0.4) = 21.80 degrees
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Ans: The 3rd angle of the triangle = 180-(71.56+21.80) = 86.64 degrees
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Cheers,
Stan H.
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