Question

Given:
AB = BC
ADB =

Answer 1

`m{\angle}D=60^(\circ)`

Explanation:

From the given figure, it can be seen that
`m{\angle}A=60^(\circ)`,
`m{\angle}B=60^(\circ)`, thus

From ΔABD, using the angle sum property, we have

`m{\angle}A+m{\angle}B+m{\angle}D=180^(\circ)`

⇒
`60^(\circ)+60^(\circ)+m{\angle}D=180^(\circ)`

⇒
`120^(\circ)+m{\angle}D=180^(\circ)`

⇒
`m{\angle}D=180^(\circ)-120^(circ)`

⇒
`m{\angle}D=60^(\circ)`

therefore, the measure of
`{\angle}ADB` is
`60^(\circ)`.

Hence, ΔABD is an equilateral triangle.

Answer 2

I hope this helps you