Answer:

Explanation:
The shape inside the circle is a quadrilateral. The following property of circle geometry can be used to solve the problem:

Proof:
Consider any quadrilateral, where the vertices touch on the circumference of a circle: ABCD, with origin O, as s
Required to prove: ∠ABC + ∠ADC = 180°
Let ∠AOC = 2x as shown in attached image.
∴ 2∠ABC = ∠AOC (using another property that "the perpendicular bisector of a chord passes through the circle's centre")
⇒ ∠ABC = x.
Now let ∠AOC = 2y.
Similarly, ∠ADC = y
⇒ ∠ABC + ∠ADC = x + y.
∵ It is clear that 2x + 2y = 360°,
⇒ x + y = 180°
∴∠ABC + ∠ADC = 180°, and hence statement is true.
Now, solving for x:
7x + 1 + 105° = 180
7x + 106 = 180
7x = 74
∴x = 74/7
Solving for y:
4y + 14 + 7y + 1 = 180
11y + 15 = 180
11y = 165
∴y = 15