1. Solving for Missing angles in Triangles

2. All 3 angles in triangle add up to 180°
A A+B+C=180° =180° B C 45
45°
45°

3. Knowing this we can solve for missing angles!
1) Add up the angles you know =95° 2) Subtract from 180° = 85° A
50°
45° ? C B

4. Some Common Combinations
Equilateral Triangles are also Equiangular .
All angles are 60°.
=180° A
B C

5. Isosceles triangles The longest side is across from the largest angle.
The other 2 angles and sides are equal.
Example:
If the large side is 120°, what are the other two?
30°
120 30 30

6.
These 3 numbers often show up together.
=180°
60°
30°

7. Lets get more complicated!
Look for familiar combinations. D 4 2 5 3 6 C
60° E

8. Right bisectors If you see a right bisector in your triangle.
It created two 90° angles. ?
30°
40°