1. a. Scalene triangle
b. Isosceles triangle
c. Right-angled triangle
d. Obtuse-angled triangle
e. Equilateral triangle
There are often alternative ways of solving triangle angle problems.
Only one way is shown below.
| 2.a. | x = 78° | (∠ sum of Δ ) |
| b. | x = 59° | (Adj. ∠ s on st. line) |
| y = 32° | (∠ sum of Δ ) | |
| c. | x = 61° | (∠ sum of Δ ) |
| y = 61° | (Vert. opp. ∠ s ) | |
| w = 119° | (Adj. ∠ s on st. line) | |
| z = 119° | (Vert. opp. ∠ s ) | |
| d. | x = 36° | (∠ sum of Δ ) |
| e. | x = 96° | (ext ∠ of Δ = sum int. opp.∠ s) |
| y = 84° | (Adj. ∠ s on st. line) | |
| f. | x = 63° | (ext ∠ of Δ = sum int. opp.∠ s) |
| g. | x = 65.5° | (∠ sum of Δ ) |
| y = 65.5° | (base ∠ s of isos. Δ ) | |
| h. | y = 47° | (base ∠ s of isos. Δ ) |
| x = 86° | (∠ sum of Δ ) | |
| i. | x = 61° | (Adj. ∠ s on st. line) |
| y = 61° | (base ∠ s of isos. Δ ) | |
| z = 58° | (∠ sum of Δ ) |
