Angles

An angle's measure determines the type of angle it is:

Right Angles - measure exactly 90°
Acute Angles - measure less than 90°
Obtuse Angles - measure more than 90° but less than 180°
Straight Angles - measure exactly 180°

Look at Figure 1. What angles are acute? What angles are obtuse? Are there any right angles? How about straight angles?

Complimentary Angles are two angles that have a sum of 90°
Supplementary Angles are two angles that have a sum of 180°

Look at Figure 1. What are two pairs of complimentary angles? What are two pair of supplementary angles?

Look at Figure 2. If angle KTR and angle RTQ are supplementary and the measure of angle KTR is 139°, what is the measure of angle RTQ? If angle QTM and angle MTK are supplementary and the measure of angle QTM is 116° what is the measure of angle MTK?

If angle KTL and angle LTN are complimentary and the measure for angle KTL is 34°, what is the measure of angle LTN? If angle QTR and angle RTS are complimentary angles, based on your measure you determined for angle QTR, what is the measure of angle RTS?

Michael Smith, August 4, 2008, Created with GeoGebra