PSLE Risa has a triangular piece of paper ABC with BA = BC, ∠ABC = 76° and ∠CDD = 73°. 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° - 76°) ÷ 2
= 104° ÷ 2
= 52° (Isosceles triangle)
∠f
= 180° - 73° - 52°
= 55° (Angles sum of triangle)
(b)
∠BAC = ∠BCA = 52°
∠h
= 180° - 73° - 73°
= 34° (Angles on a straight line)
∠g
= 180° - 52° - 34°
= 94° (Angles sum of triangle)
Answer(s): (a) 55°; (b) 94°