Class 8, Maths, Chapter 3, Exercise 3.1, Solutions
Q.1. Given here are some figures:
Classify each of them on the basis of the following.
(a) Simple curve
(b) Simple closed curve
(c) Polygon
(d) Convex polygon
(e) Concave polygon
Ans: (a) Simple curve = (1), (2), (5), (6), (7)
(b) Simple closed curve = (1), (2), (5), (6), (7)
(c) Polygon = (1), (2)
(d) Convex polygon = (2)
(e) Concave polygon = (1)
Q.2. How many diagonals does each of the following have?
(a) A convex quadrilateral
(b) A regular hexagon
(c) A triangle
Ans:
Q.3. What is the sum of the measures of the angles of a convex quadrilateral? Will this property hold if the quadrilateral is not convex? (Make a non-convex quadrilateral and try!)
Ans:
Q.4. Examine the table. (Each figure is divided into triangles and the sum of the angles deduced from that.)
What can you say about the angle sum of a convex polygon with number of sides?
(a) 7
(b) 8
(c) 10
(d) n
Ans: we know that, (Side – 2) x 1800
(a) 7
(Side – 2) x 1800
(7 – 2) x 1800 = 5 x 180 = 9000
(b) 8
(8 – 2) x 1800 = 6 x 180 = 10800
(c) 10
(10 – 2) x 1800 = 8 x 180 = 12600
(d) n
(n – 2) x 1800 = n x 1800
Q.5. (a) What is a regular polygon?
(b) State the name of a regular polygon of
(i) 3 sides
(ii) 4 sides
(iii) 6 sides
Ans:
Q.6. Find the angle measure x in the following figures.
NCERT Solutions For Class 8 Maths Chapter 3, Understanding Quadrilaterals (All Exercises)
Class 8, Maths, Chapter 3, Understanding Quadrilaterals
Class 8, Maths, Chapter 3, Understanding Quadrilaterals, Exercise 3.1 ← You are here
Class 8, Maths, Chapter 3, Understanding Quadrilaterals, Exercise 3.2
Class 8, Maths, Chapter 3, Understanding Quadrilaterals, Exercise 3.3
Class 8, Maths, Chapter 3, Understanding Quadrilaterals, Exercise 3.4