In the diagram shown, ABCDABCDABCD is a square and point FFF lies on BC.BC.BC. △DEC△DEC△DEC is equilateral and EB=EF.EB=EF.EB=EF. What is the measure of ∠EBC?∠EBC?∠EBC?
Answer:
75∘75∘75∘
- Given, ABCDABCDABCD is a square, △DEC△DEC△DEC is an equilateral triangle and EB=EF.EB=EF.EB=EF.
⟹∠DCB=90∘ and ∠DCE=60∘⟹∠DCB=90∘ and ∠DCE=60∘⟹∠DCB=90∘ and ∠DCE=60∘
⟹∠ECF=30∘⟹∠ECF=30∘⟹∠ECF=30∘ - Since DC=CE DC=CE DC=CE [Sides of an equilateral triangle]
and DC=CB DC=CB DC=CB [Sides of a square]
⟹CE=CB⟹CE=CB⟹CE=CB
⟹△ECB⟹△ECB⟹△ECB is an isosceles triangle.
⟹∠EBC=∠BEC [∵Angles opposite to equal sides of a triangle are equal]
Now, ∠ECB+∠EBC+∠BEC=180∘ [ Angle Sum Property of a triangle]
⟹∠EBC+∠EBC+30∘=180∘
⟹∠EBC=(180−30)2=75∘ - Given, EB=EF
∴∠BFE=∠EBC=75∘ - Hence, the value of ∠EBC is ∠75∘.