PSLE CDEF and EHKG are identical parallelograms. JED and GFE are identical right-angled triangles.
- Find ∠l.
- Find ∠m.
- Select the words that describe DJH in the statement:
DJH (is/is not) a straight line because the sum of angles DJE and EJH (is/is not) 180° Give your answers in this format. (Eg is, is not)
(a)
∠l
= 180° - 76°
= 104° (Interior angles)
(b)
∠GEH
= ∠DEF
= 104° (Parallelogram)
∠DEJ
= 180° - 90° - 19°
= 71° (Angles sum of triangle)
∠m
= 360° - 104° - 104° - 19° - 71°
= 62° (Angles at a point)
(c)
∠EJH
= 180° - 29° - 62°
= 89°
Since ∠EJH is not 90°, it does not add up to 180° with ∠DJE to form a straight line. So, DJH
is not a straight line because the sum of angles DJE and EJH
is not 180°.
Answer(s): (a) 104°; (b) 71°; (c) is not, is not