Friday, January 14, 2011

Geometry-June 2009 NYS Regents Exam

1. Jultann plans on drawing Triangle ABC, where the measure of angle A can range from 50 degrees to 60 degrees and the measure of angle B can range from 90 degrees to 100 degrees. Given these conditions, what is the correct range of measures possible for angle C?

In a triangle, there are 3 interior angles which adds up to 180 degrees.

a) If we use the lowest degrees in using the formula (MEASURE OF ANGLE "A" + MEASURE OF ANGLE "B" + MEASURE OF ANGLE "C" = 180 DEGREES), then we see that 50 and 90 are the lowest degrees in angle A and B, but we don't know C, and the triangle equals to 180 degrees. We then add 50 degrees and 90 degrees and come up with 140 degrees. So, Angle C is 180 degrees which is the total degree in a triangle minus 140 degrees for Angle A and B, which equals to 40 degrees. Hence, Measure of Angle C is 40 degrees.

b) If we use the highest degrees in using the formula (MEASURE OF ANGLE "A" + MEASURE OF ANGLE "B" + MEASURE OF ANGLE "C" = 180 DEGREES)then we see that 60 and 100 are the highest degrees in angle A and B, but we don't know C, and the triangle equals to 180 degrees. We then add 60 degrees and 100 degrees and come up with 160 degrees. So, angle C is 180 degrees which is the total degree in a triangle minus 160 degrees for angle A and B, which equals to 20 degrees. Hence, Measure of Angle C is 100 degrees.

So, the correct answer to this problem would be 20 degrees to 40 degrees is the correct range of measures possible for Angle C.

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