MP Board Class 8th Maths Solutions Chapter 3 Understanding Quadrilaterals Ex 3.2
Question 1.
 Find x in the following figures.
 
 Solution:
 (a) Sum of the measures of the exterior angles of any polygon is 360°.
 ∴ 125° + 125° + x = 360°
 ⇒ 250° + x = 360°
 ⇒ x = 360° – 250° ⇒ x = 110°.
 (b) Since, sum of the exterior angles of any polygon is 360°.
 ∴ x + 90° + 60° + 90° + 70° = 360°
 ⇒ x + 310° = 360° => x = 360° – 310°
 ∴ x = 50°.

Question 2.
 Find the measure of each exterior angle of a regular polygon of
 (i) 9 sides
 (ii) 15 sides.
 Solution:
 (i) Let each exterior angle of a regular polygon who has 9 sides is equal to x.
 Sum of exterior angles of any polygon is 360°.
 
 Thus each exterior angle of a regular polygon of 9 sides is 40°.
 (ii) Let each exterior angle of a regular polygon who has 15 sides is x.
 Sum of all exterior angles of a polygon is 360°.
 
 Thus each exterior angle of a regular polygon of 15 sides is 24°.

Question 3.
 How many sides does a regular polygon have if the measure of an exterior angle is 24°?
 Solution:
 Total measure of all exterior angles = 360°
 Measure of each exterior angle = 24°
 Therefore, the number of sides = \(\frac{360^{\circ}}{24^{\circ}}\)
 = 15
 The polygon has 15 sides.
Question 4.
 How many sides does a regular polygon have if each of its interior angles is 165°?
 Solution:
 Total measure of all exterior angles = 360°
 Measure of each interior angle = 165°
 Measure of each exterior angle = 180° – 165°
 = 15°
 Therefore, number of sides = \(\frac{360^{\circ}}{15^{\circ}}\) = 24

Question 5.
 (a) Is it possible to have a regular polygon with measure of each exterior angle as 22°?
 (b) Can it be an interior angle of a regular polygon? Why ?
 Solution:
 (a) No, because 22° is not a divisor of 360°.
 (b) No, because each interior angle is 180° – 22° = 158°, which is not a divisor of 360°.
Question 6.
 (a) What is the minimum interior angle possible for a regular polygon? Why?
 (b) What is the maximum exterior angle possible for a regular polygon?
 Solution:
 (a) Since each angle of an equilateral triangle is 60°.
 And equilateral triangle is a regular polygon.
 ∴ Minimum interior angle is 60° for a regular polygon.
 (b) Since minimum interior angle of a regular polygon is 60°.
 ∴ Each exterior angle of a regular polygon = 180° – 60° = 120°.
 ∴ Possible maximum exterior angle of a regular polygon is 120°.

























































