Question

2C and ZD are vertical angles with mzC= -2.1 +90 and mZD=x - 30. What is mZD?

Answer 1

We know that angles ZC and ZD are vertical angles, this means they are equivalent by definition.

`m\angle ZC=m\angle ZD`

Replacing the given expressions-

`-2.1+90=x-30`

First, we have to reduce like terms

`87.9=x-30`

Now, we sum 30 on each side

`\begin{gathered} 87.9+30=x-30+30 \\ 117.9=x \end{gathered}`

We use this value to find angle ZD.

`m\angle ZD=x-30=117.9-30=87.9`

Therefore, angle ZD is equal to 87.9°