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° - 79°
= 101° (Interior angles)
(b)
∠FDG
= ∠CDE
= 101° (Parallelogram)
∠CDH
= 180° - 90° - 21°
= 69° (Angles sum of triangle)
∠l
= 360° - 101° - 101° - 21° - 69°
= 68° (Angles at a point)
(c)
∠DHG
= 180° - 26° - 68°
= 86°
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) 101°; (b) 69°; (c) is not, is not