PSLE DEFG and FJLH are identical parallelograms. KFE and HGF are identical right-angled triangles.
- Find ∠m.
- Find ∠n.
- Select the words that describe EKJ in the statement:
EKJ (is/is not) a straight line because the sum of angles EKF and FKJ (is/is not) 180° Give your answers in this format. (Eg is, is not)
(a)
∠m
= 180° - 79°
= 101° (Interior angles)
(b)
∠HFJ
= ∠EFG
= 101° (Parallelogram)
∠EFK
= 180° - 90° - 23°
= 67° (Angles sum of triangle)
∠n
= 360° - 101° - 101° - 23° - 67°
= 68° (Angles at a point)
(c)
∠FKJ
= 180° - 22° - 68°
= 90°
Since ∠FKJ is 90°, it adds up to 180° with ∠EKF to form a straight line. So, EKJ
is a straight line because the sum of angles EKF and FKJ
is 180°.
Answer(s): (a) 101°; (b) 67°; (c) is, is