CDEF is a quadrilateral and OCFE is a trapezium in which OC // FE and ∠DCF = 113°, ∠CFE = 124°, ∠DEF = 62° and FE = FC. Find
- ∠CDO
- ∠FCO
- ∠CEF.
(a)
∠CDO
= 360° - 124° -113° - 62°
= 61° (Sum of angles in a quadrilateral)
(b)
∠FCO
= 180° - 124°
= 56° (Interior angles, CO//FC)
(c)
∠CEF
= (180° - 124°) ÷ 2
= 56 ÷ 2
= 28° (Isosceles triangle)
Answer(s): (a) 61°; (b) 56°; (c) 28°