Answer:
Part A
a. Could be a parallelogram but cannot be a rectangle
Part B
c. 100°
Explanation:
Part A
The polygon constructed by Andrew = Four sided polygon having no right angles
From the given four sided polygon (quadrilateral) options, the options which can have no right angles are the parallelogram, and rhombus
The rectangle, and square both have 4 right angles
Therefore, the polygon can be either a parallelogram or a rhombus, but cannot be either a rectangle or square
The correct option is therefore, 'His polygon could be a parallelogram but cannot be a rectangle'
Part B
The given parameters of the rhombus EFGH are;
Angle E = 3·x + 5, angle H = 4·x
The characteristics of a rhombus are;
The sum of the interior angles of a rhombus = 360°
The opposite angles of a rhombus are equal
The sum of the adjacent angles = 180° (The adjacent angles are supplementary)
Therefore, in the rhombus EFGH, we have;
Angle E, and angle H are supplementary angles
∴ Angle E + angle H = 180°
Substituting the values of angle E and angle H gives;
3·x + 5 + 4·x = 180°
7·x = 180° - 5 = 175°
x = 175°/7 = 25°
Angle H = 4·x
∴ Angle H = 4 × 25° = 100°
Angle H = 100°
Angle F = angle H = 100°
Therefore, angle F = 100°