question 6, 8 and 7 chapter perimeter and area class 7
Answers
Answer:
Step-by-step explanation:
Q6
Perimeter of a circle park=πr
72=πr
r=23cm
Area of semicircular park=πr^2/2
Area of semicircular park=π(23)^2/2
Area of semicircular park=831cm^2
Q8
The radius of circle = 8cm
diameter = 8*2 = 16cm
The diameter of circle = diagonal of square = 16cm
area of square = (diagonal)²/2 = 16²/2 = 128cm²
Q7Length of wire = 440 m
So, this will be considered as the perimeter for a square and circumference for a circle.
So, according to the question.
Circumference of circle = 2πr
440 = 2*22/7*r
44r = 440*7
r = (440*7)/44
Radius of the circle = 70 m.
Now, area of the circle = πr²
= 22/7*70*7
Area of the circle = 15400 sq m
Now,
Perimeter of the square = 440 m
Each side of square = Perimeter/4
= 440/4
Each side of square = 110 m
Now,
Area of the square = side × side
= 110 × 110
Area of the square = 12100 sq m
Now,
Ratio of the area of the circle to that the area of the square.
= 15400 : 12100
Ratio = 14 : 11
Answer:
Step-by-step explanation:
Q6
Perimeter of a circle park=πr
72=πr
r=23cm
Area of semicircular park=πr^2/2
Area of semicircular park=π(23)^2/2
Area of semicircular park=831cm^2
Q8
The radius of circle = 8cm
diameter = 8 x 2 = 16cm
The diameter of circle = diagonal of square = 16cm
area of square = ²/2 = 16²/2 = 128cm²
Q7Length of wire = 440 m
So, this will be considered as the perimeter for a square and circumference for a circle.
Circumference of circle = 2πr
440 = 2 x 22/7x r
44r = 440 x 7
r = (440 x 7)/44
Radius of the circle = 70 m.
Now, area of the circle = πr²
= 22/7 x 70 x 7
Area of the circle = 15400 sq m
Now,
Perimeter of the square = 440 m
Each side of square = Perimeter/4
= 440/4
Each side of square = 110 m
Now,
Area of the square = side × side
= 110 × 110
Area of the square = 12100 sq m
Now,
Ratio of the area of the circle to that the area of the square.
= 15400 : 12100
Ratio = 14 : 11