PSLE BCDE and DGJF are identical parallelograms. HDC and FED are identical right-angled triangles.
- Find ∠k.
- Find ∠l.
- Select the words that describe CHG in the statement:
CHG (is/is not) a straight line because the sum of angles CHD and DHG (is/is not) 180° Give your answers in this format. (Eg is, is not)
(a)
∠k
= 180° - 72°
= 108° (Interior angles)
(b)
∠FDG
= ∠CDE
= 108° (Parallelogram)
∠CDH
= 180° - 90° - 29°
= 61° (Angles sum of triangle)
∠l
= 360° - 108° - 108° - 29° - 61°
= 54° (Angles at a point)
(c)
∠DHG
= 180° - 33° - 54°
= 93°
Since ∠DHG is not 90°, it does not add up to 180° with ∠CHD to form a straight line. So, CHG
is not a straight line because the sum of angles CHD and DHG
is not 180°.
Answer(s): (a) 108°; (b) 61°; (c) is not, is not