Question

13. Find the value of x.

124
136
132
158
129
142
116
need ASAP!!

Answer 1

The Solution.

The sum of interior angles of a polygon is given by:

`\begin{gathered} \text{Sum = (n-2)180} \\ \text{where n =number of sides} \end{gathered}`

Substituting 6 for n in the formula above, we get

`\begin{gathered} \text{Sum =(6-2)180} \\ \text{Sum = 4}*180=720^o \end{gathered}`

So,

`\begin{gathered} 78+134+136+132+2x+x=720 \\ \text{collecting like terms, we get} \end{gathered}`
`\begin{gathered} 480+3x=720 \\ 3x=720-480 \\ 3x=240 \\ \text{Dividing both sides by 3, we get} \\ x=(240)/(3)=80^o \end{gathered}`

Thus, the correct answer is 80 degrees (option C)