# Question #7b017

##### 1 Answer

Mar 25, 2017

Not valid.

#### Explanation:

The

#color(blue)"sum of the angles at a point" =360^@# To find z, sum the 4 given angles and subtract the result from 360.

#rArr(2xx108^2)+(2xx72^@)=216+144=360^@# The 4 given angles make up the sum.