Question

ABCD is a cyclic trapezium with AD || BC. If ∠B = 70°, determine other three angles of the trapezium.

Answer 1

If in cyclic quadrilateral , then we have to find the other three angles.

Since, AD is parallel to BC, So,
(Alternate interior angles)

Now, since ABCD is cyclic quadrilateral, so

And,

$\mathrm{Hence},\angle A=110°,\angle C=70°\mathrm{and}\angle D=110°$.