SOLUTION: The base angle of an isosceles triangle is 30. What is the measure of the vertex angle? also: A bottled water company charges $8 per month for a water cooler and $5 per bott

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Question 236754: The base angle of an isosceles triangle is 30. What is the measure of the vertex angle?
also:
A bottled water company charges $8 per month for a water cooler and $5 per bottle b of water. Write an equation that represents the total cost C for monthly water service.
Answer by nyc_function(2741) About Me  (Show Source):
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The base angle of an isosceles triangle is 30. What is the measure of the vertex angle?
Isosceles triangles have 2 equal base angles.
The vertex is the top angle which is usually cut by a line from the vertex to the bottom part of the isosceles triangle.
This line creates two right triangles.
We were given one angle to be 30 degrees.
Each right triangle has a 90-degress angle.
We now have 90 + 30.
To find the other angle, subtract 30 from 90 or 60 degrees.
The vertex angle = 2 times the angle we found by subtracting 30 from 90.
The vertex angle = 2(60) or 120 degrees.