PSLE LMNP and NRTQ are identical parallelograms. SNM and QPN are identical right-angled triangles.
- Find ∠u.
- Find ∠v.
- Select the words that describe MSR in the statement:
MSR (is/is not) a straight line because the sum of angles MSN and NSR (is/is not) 180° Give your answers in this format. (Eg is, is not)
(a)
∠u
= 180° - 75°
= 105° (Interior angles)
(b)
∠QNR
= ∠MNP
= 105° (Parallelogram)
∠MNS
= 180° - 90° - 20°
= 70° (Angles sum of triangle)
∠v
= 360° - 105° - 105° - 20° - 70°
= 60° (Angles at a point)
(c)
∠NSR
= 180° - 31° - 60°
= 89°
Since ∠NSR is not 90°, it does not add up to 180° with ∠MSN to form a straight line. So, MSR
is not a straight line because the sum of angles MSN and NSR
is not 180°.
Answer(s): (a) 105°; (b) 70°; (c) is not, is not