AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3

SCERT AP 7th Class Maths Solutions Pdf Chapter 11 Area of Plane Figures Ex 11.3 Textbook Exercise Questions and Answers.

AP State Syllabus 7th Class Maths Solutions 11th Lesson Area of Plane Figures Ex 11.3

Question 1.
The diameter of the round table upper surface in the Science lab is 70 cm. Find the area.
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 1
Answer:
Given diameter of table d = 70 cm
Radius of table r = \(\frac{\mathrm{d}}{2}\) = \(\frac{70}{2}\) = 35 cm
Area of the table = πr²

∴ Area of the round table = 3,850 sq.cm.

Question 2.
Radius of the circular shaped wall painting is 14 cm. Calculate the area of wall painting.
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 3
Answer:
Given radius of the wall painting
r = 14 cm
Area of the circle = πr²
= \(\frac{22}{7}\) × 14²

= 616
∴ Area of the wall painting = 616 sq.cm

Question 3.
If the area of circular shaped dart board is 1386 sq.cm. Find its radius and diameter.
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 5
Answer:
Given the area of circular shaped dart board = 1386 sq.cm
Area of the circle = πr² = 1386
⇒ \(\frac{22}{7}\) × r² = 1386
⇒ 22 × r² = 1386 × 7

⇒ r² = 441 = 21²
⇒ r² = 21²
∴ Radius of dart board r = 21 cm
Diameter of dart board d 2r
= 2 × 21
= 42 cm

Question 4.
Circumference of the circular shaped clock is 44 cm. Find the radius and surface area of the clock.
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 7
Answer:
Given the circumference of clock = 44 cm
⇒ 2πr = 44 cm
⇒ 2 × \(\frac{22}{7}\) × r = 44
⇒ 44 × r = 44 × 7

∴ Radius of the clock r = 7 cm
Surface area of the clock = πr²
= \(\frac{22}{7}\) × 7²
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 9
∴ Surface area of the clock = 154 sq.cm

Question 5.
The circumference of a circular-shaped lawn in a park is 352 m. Find the area of the circular-shaped lawn. If the cost of grass per sq. m is ₹ 30, then find the total cost of laying grass on the lawn.
AP Board 7th Class Maths Solutions Chapter 11 Area of Plane Figures Ex 11.3 10
Answer:
Given the circumference of lawn = 352 m
⇒ 2πr = 352 m
⇒ 2 × \(\frac{22}{7}\) × r = 352
⇒ 44r = 352 × 7 7

∴ Radius of the lawn r = 56 m
Area of the lawn = πr²
= \(\frac{22}{7}\) × 56²

Area of the lawn = 9856 sq.m
Cost of grass per sq.m = ₹ 30
Cost of grass per 9856 sq.m = 9856 × 30
∴ Total cost of laying grass on lawn = ₹ 2,95,680