Question

How to find X for number 8

Answer 1

`x=105`°

Explanation:

Given:

Let us label the vertices of the figure as shown below.

Consider triangle CDE. The exterior angle CDB is equal to the sum of opposite interior angles. Therefore,

`\angle CDB=\angle CED+\angle DCE\\\angle CDB=80+50=130\°`

Now, for a quadrilateral ABDX, the exterior angle DXC is given as:

`\angle DXC=\angle BAX+\angle ABD+\angle XDB-180\\x=65+90+130-180\\x=285-180=105\°`

Therefore,
`x=105\°`