Triangles & angles.

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Triangles & angles

Algebra Section 3-4 Supplementary angles - Two angles are supplementary if the sum of their measure is 180. Complementary angles - Two angles are complementary if the sum of their measure is 90. Sum of the angles of a triangle - The sum of the measures of the angles in any triangle is 180.

Section 3-4 definitions cont.
Triangle - a polygon with tree sides and three angles. Equilateral Triangle - each angle’s measure is the same. Isosceles Triangle - at least two of the angles have the same measurement. Right triangle - has one angle that is 90 degrees.

Section 3-4 Examples The measure of an angle is three times the measure of its supplement. Find the measure of each angle. X +3x = 180 4x = 180 4x/4 = 180/4 ( divide both sides by 4) x = 45 Thus the measures are 45 and 3 x 45 or 135

Section 3-4 Examples The measure of an angle is 34 greater than its complement. Find the measure of each angle. x + (x + 34) = 90 2x + 34 = 90 2x = (subtract 34 from both sides) 2x = 56 2x/2 = 56/2 ( divide both sides by 2) x = 28 The measures are 28 and ( ) or 62