Assuming you need an answer to question #7, here it is.
The sum of all angles inside a polygon depends on the number of sides it has. (n-2) x 180°, where n is the number of sides. Knowing there are 5 sides to the polygon, we can figure out the sum of its interior angles :
(5-2) x 180° = 3x180° = 540°
We know the values of the two right angles on the right side of the shape. They both are of 90° (aka right angle) and add up to 180°. This means that the other angles must make up the rest : 540° (Total) - 180° (right side) = 360° (total of angles A, B and C).
Now we need to make relations between these unknown angles.
1. A=B They were described as having the same size;
2. A=2C A and B were described as being twice as big as C, so we would need two times C to equal A;
3. A+B+C = 360° Which we figured out earlier.
Since B=A we can replace B in the third equation :
A+A+C = 360°
2A+C = 360°
We also know that A=2C :
2(2C)+C=360°
4C+C=360°
5C=360°
We solve for C :
C=72°
Now that we know the value of angle C, we can work our way up towards angles A and B.
A=2C
A=2(72°)
A=144°
B=A
B=144°
We can verify our values to see if it all makes sense.
Is A+B+C=360° still true?
144°+144°+72°=360°
360°=360°
Thus, angles A, B and C are respectively 144°, 144° and 72°.