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° - 76°
= 104° (Interior angles)
(b)
∠HFJ
= ∠EFG
= 104° (Parallelogram)
∠EFK
= 180° - 90° - 26°
= 64° (Angles sum of triangle)
∠n
= 360° - 104° - 104° - 26° - 64°
= 62° (Angles at a point)
(c)
∠FKJ
= 180° - 25° - 62°
= 93°
Since ∠FKJ is not 90°, it does not add up to 180° with ∠EKF to form a straight line. So, EKJ
is not a straight line because the sum of angles EKF and FKJ
is not 180°.
Answer(s): (a) 104°; (b) 64°; (c) is not, is not