Q1.work out the sum of the interior angles of a pentagon. Q2.work out the size of one interior angle of a regular octagon.
Q3.work out the size of one exterior angle of a regular hexagon

Question 1:

The sum of interior angles of a polygon can be found by the following formula:

(n-2) × 180

Where n is the no. of sides

A pentagon has 5 sides

So,

= (5-2) × 180

= (3) × 180

= 540 degrees

Question 2:

Since The sum of interior angles of a regular octagon is 1080 and the total interior angle are 8

So, Measure of interior angle =

Measure of interior angle = 135 degrees

Question 3:

Since, one interior angle in a hexagon measures 120 degrees.

So,

The interior angle should be subtracted by 180 to get the exterior angle.

Exterior angle = 180-120

Exterior Angle = 60 degrees

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.