WAEC 2025 · Paper 1 · Q41✱✱

In the diagram, BB lies on ADAD, CC lies on AEAE, and DCDC meets BEBE at FF. The angles marked a∘a^\circ are equal. Find b+cb + c.

a°a°a°b°c°ABCDEF
Worked solution (try it first)
  1. BFEBFE is a straight line, so ∠BFC=180∘−a\angle BFC = 180^\circ - a (it sits next to the aa at FF).
  2. The angles of quadrilateral ABFCABFC add up to 360∘360^\circ: a+b+(180−a)+c=360a + b + (180 - a) + c = 360.
  3. The aas cancel: b+c+180=360b + c + 180 = 360, so b+c=180∘b + c = 180^\circ, option C.

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