Friday, March 4, 2011

Measure of Angle


Arc BC 2 X 60 degrees = 120 degrees

m

m
Angle is 1/2 of Arc therefore 120 degrees Arc's 1/2 is 60 degrees in angle.

measure of Arc EBA = BE - CE = 180 - 40 divide by 2 = 140/2 = 70 degrees.

4) In circle O, FA is a tangent, FEDB is a secant, ADC and AB are chords, mCE = 40D, mAB = 130D, and mACAB = 60D.

Find:
(a) mBC
(b) mAEBA
(c) mAADE
(d) mAF
(e) mAFAC

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.