$supplementary angle theorem$

Simply use the triangle angle sum theorem to find the missing angle: Both angle C and angle D have measures equal to 180 x and are congruent. Similarly, the measure of angle D would be 180 x. Therefore, if we assume that the measure of angle A equals x, then the measure of angle C would be 180 x. From this theorem we can find the missing angle: γ = 180°- α - β When two adjacent angles form a straight line, they are supplementary. As you know, the sum of angles in a triangle is equal to 180°. Linear Pair Theorem/ Equal supplementary angles Theorem/ Equal supplements Theorem.For example, assume that we know a, b, α: Details: Solution: Add the given two angles and check if the resultant angle is 180 or not. If angle QRT is 40, and angle TRS is 83, then angle QRS is 123.

If the angle isn't between the given sides, you can use the law of sines. Explain, Justify, and Use Supplementary Angle Theorem. then find β from triangle angle sum theorem: β = 180°- α - γ.If the angle is between the given sides, you can directly use the law of cosines to find the unknown third side, and then use the formulas above to find the missing angles, e.g. Use the formulas transformed from the law of cosines:

Supplementary angle theorem