The following are coming from your notes. This will just help you solve each questions.

Now follow the same steps to answer both number 3 & 4.

But for no. 3&4, after getting the sum of interior angles, you still have to divide it by the no. of sides.

Steps in solving missing angle

Same thing will be done in no 13 - 17,

First, find the sum of interior angles of the polygon

Second, add all the angles inside

Lastly, subtract the sum of interior angles by the sum of the given angles inside.

No. 13

First, find the sum of interior angles of the polygon.
Use 180 (n-2).

Second, sum of all the given angles inside.

Lastly, subtract the sum of interior angles by the sum of the given angles inside.

No. 14, may use Desmos

First, find the sum of interior angles of the polygon which is 720.

Second, sum of all the given angles inside.

Lastly, use Desmos to solve for x by equating both
sum of all given angles = 360

No. 15, may use Desmos

First, find the sum of interior angles of the polygon which is 360.

Second, sum of all the given angles inside.

Lastly, use Desmos to solve for x by equating both
sum of all given angles = 360

No. 16, may use Desmos

First, find the sum of interior angles of a decagon.

Second, divide the answer by the no. of sides.

Lastly, use Desmos to solve for x by equating the given 10x + 4 and your answer from the second step.

No. 17, may use Desmos

Use Desmos to solve for x by equating the sum all the given angles = 360

Submit your paper to your teacher when done!