JAMB 1987 · UME · Q46

Taking the period of daylight on a certain day to be from 5.30 a.m. to 7.00 p.m., calculate the angles (in a pie chart) for the periods of daylight and of darkness on that day.

Worked solution (try it first)
  1. From 5.30 a.m. to noon is 6126\frac12 hours, and from noon to 7.00 p.m. is 7 hours, so daylight lasts 131213\frac12 hours.
  2. Daylight angle: 13.524×360∘=202.5∘\frac{13.5}{24} \times 360^\circ = 202.5^\circ
    =202∘30′= 202^\circ30'.
  3. Darkness takes the rest: 360∘−202∘30′=157∘30′360^\circ - 202^\circ30' = 157^\circ30', option C.

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