Question

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Answer 1

Question (1)

Given :---

• Ratio of radii of two circle = 5:4

we have to Find its circumference ratio...

Let radii of two circle be = 5x and 4x

we know that circumference of circle = 2πr

so,

Ratio of their circumference will be :-----

2π(5x) : 2π(4x)

5 :4 (Ans)

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Question (2)

Given :-----

• circumference of inner circle = 220m
• width of path = 7m
• rate of fence = Rs. 50 per metre

Solution :-------

Since circumference of inner circle = 220m

2πr = 220

2 × 22/7 × r = 220

r = 220×7/22×2

r = 35 cm

So, radius of outer circle = radius of inner circle + width

Radius of outer circle = 35+7 = 42 cm

its circumference = 2×22/7×42 = 264m

so,

cost of fencing = 264 × 50 = Rs.13200 (Ans)

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Question (3)

Diameter of wheel = 70cm

We have to Find how many round it will take to complete 99km ..

we know that ,

1km = 1000m

1m = 100 cm

so,

99km = 99×1000×100 cm = 99,000,00 cm

Now, in round wheel cover distance = its circumference length .

so,

circumference of wheel =

2×22/7× 70 = 440cm .

Now to cover given distance ,

Number of round will be = 9900000/440 = 22,500 Rounds..

so, wheel will take 22,500 Rounds to cover 99km...

(Hope it helps you)