Question

plzz solve this question ☝

Answer 1

In triangle DEC AND EBF
Angle E =angle E
Angle D =angle B . Alternate in. Angle
DE=EF
hence both triangles are congruent
So FB=DC
AND DC =AB
HenceAB=1/2AF
so, AF=2AB


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Answer 2

Step-by-step explanation:

consider Δdec & Δbef

be = ce (given)

∠ced = ∠bef ( vertically opposite angles )

∠cbf = ∠bcd ( dc ║ ab and bc as transversal [ alternate interior angles})

∴ Δdec ≅ Δbef ( by asa ≅)

so dc = bf ( by cpct ) .................(i)

and ab = dc (opposite sides of a parallelogram are equal) ................... (ii)

from (i) & (ii) we get

ab = bf ....................(iii)

and we know that ab + bf = af ......................(iv)

from (iii) &(iv)

we get ab + bf = af

=>ab + ab = af

=> 2ab = af

hence proved