Use the foil method to multiply out the expressions. Then solve for x by first combining like terms and then using inverse properties
Corresponding angle postulate
<u>Answer:</u>
An obtuse triangle has two angles 45 and 18. The value of the unknown angle is 
<u>Solution:</u>
Given that two angles of an obtuse triangle is 45 and 18.
Third angle is θ
We are asked to find the value of third unknown angle theta
According to <em>angle sum property of triangle</em>, sum of three angles of triangle is 
This means in our case sum of 45, 18 and θ should be 

Hence value of unknown third angle of an obtuse triangle is