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A) work out the size of angle AED
B) Work out X

A) work out the size of angle AED B) Work out X-example-1
User Eliko
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1 Answer

1 vote

Answer: x = 10°

Explanation:

Since, opposite angles of a cyclic quadrilateral are supplementary angles"

Therefore, in cyclic quadrilateral ABDE,

m∠ABD + m∠AED = 180°

110° + m∠AED = 180°

m∠AED = 180° - 110°

= 70°

AD = ED [Given]

m∠EAD = m∠AED [Since, opposite angles of equal sides are equal in measure]

m∠EAD = m∠AED = 70°

By triangle sum theorem in ΔABD,

m∠BAD + m∠ABD + m∠ADB = 180°

m∠BAD + 110° + 40° = 180°

m∠BAD = 180 - 150

= 30°

m∠AEB = m∠AED + m∠DAB [By angles addition postulate]

m∠AEB = 70° + 30°

= 100°

By triangle sum theorem in the large triangle,

x° + m∠AEB + m∠EAB = 180°

x° + 100° + 70° = 180°

x = 180 - 170

x = 10°