PSLE Dana has a triangular piece of paper ABC with BA = BC, ∠ABC = 82° and ∠CDD = 75°. ADC and BDC are straight lines. She folded it along the line DE as shown.
- Find ∠f.
- Find ∠g.
(a)
Length of AB = Length of BC
Triangle ABC is an isosceles triangle.
∠BCA
= (180° - 82°) ÷ 2
= 98° ÷ 2
= 49° (Isosceles triangle)
∠f
= 180° - 75° - 49°
= 56° (Angles sum of triangle)
(b)
∠BAC = ∠BCA = 49°
∠h
= 180° - 75° - 75°
= 30° (Angles on a straight line)
∠g
= 180° - 49° - 30°
= 101° (Angles sum of triangle)
Answer(s): (a) 56°; (b) 101°