Question

In triangle abc ,if ab=ac and ab is produced to d such that angle acd = 100 angle a =?

Answer 1

suppose the answer is 80 degrees

Answer 2

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➨We have ,

→ ZACD + ZACB = 180 ° [ Linear Pair ]

→ 100 ° + ZACB = 180 °

→ ZACB = 180 ° - 100 °

→ ZACB = 80 °

➨From ( i ) & ( ii ) ,

➨ We get

➨ Angle ZABC = Angle ZACB = 80 °

➨Now ,

→ ZABC + ZACB + ZA = 180º .... [ Sum of the 3 interior angles of a triangle is 180° ]

→ Substituting the values of ZABC & ZACB ,

➨ We get

→ 80 ° + 80 ° + A = 180 °

→ 160 ° + A = 180 °

→ A = 180 ° - 160 °

→ A = 20 °

Thus , the measure of Angle ‘A’ is 20 °