Area and Perimeter
- The perimeter of an isosceles triangle is 26 cm while equal sides together measure 20 cm. The third side and each of the equal sides are respectively.
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Let the third side be x.
According to the question,
x + 20 = 26Correct Option: A
Let the third side be x.
According to the question,
x + 20 = 26
⇒ x = 26 - 20 = 6 cm
∴ Each equal side = 20/2 = 10 cm
- The ratio of length and breadth of a rectangle is 5 : 3 .If length is 8 m more than breadth, find the area of the rectangle.
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Let length of rectangle = 5k
and breadth of rectangle = 3k
According to the quecation,
5k - 3k = 8
Required area = Lenght x BreadthCorrect Option: C
Let length of rectangle = 5k
and breadth of rectangle = 3k
According to the quecation,
5k - 3k = 8
⇒ 2k =8
∴ k = 4
∴ Lenght = 5k = 5 x 4 = 20 m
Breadth = 3k = 3 x 4 = 12 m
∴ Required area = Lenght x Breadth
= 20 x 12 = 240 sq m
- The ratio between the lenght and the breadth of a rectangle is 2 : 1. If breadth is 5 cm less than the length, what will be the parimeter of the rectangle?
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Let length = 2x and breadth = x
According to the question,
2x - x = 5
∴ Required perimeter = 2(2x + x)Correct Option: A
Let length = 2x and breadth = x
According to the question,
2x - x = 5
⇒ x = 5
∴ Required perimeter = 2(2x + x)
= 6x
= 30 cm
- A person observed that he required 30 s time to cross a circular ground along its diameter than to cover it once along the boundary. If his speed was 30m/min, than the radius of the circular ground is (take π = 22/7)
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Let the radius of circular field = r m.
Speed of person in m/s = 30/60 = 1/2m/s
According to the question,
[(2πr) /(1/2)] - [(2r)/(1/2)] = 30Correct Option: B
Let the radius of circular field = r m.
Speed of person in m/s = 30/60 = 1/2m/s
According to the question,
[(2πr) /(1/2)] - [(2r)/(1/2)] = 30
⇒ 4πr - 4r = 30
⇒ [4 x (22/7) - 4]r =30
⇒ (125 - 4)r = 30
⇒ (8.5)r = 30
⇒ r = 30/8.5 = 3.5 m
- A man riding a bicycle, completes one lap of a circular field along its circumference at the speed of 14.4 km/h in 1 min 28 s. What is the area of the field?
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The man takes 3600 s for 14.4 km
The man will take 88 s for
14.4 x (88/3600) = 352/1000 km = 352 m
Now, circumference of circular field = 352 m
⇒ 2πr = 352 m
2 x (22/7) x r = 352
⇒ r = 56 m
Therefore, area of the field = πr2Correct Option: B
The man takes 3600 s for 14.4 km
The man will take 88 s for
14.4 x (88/3600) = 352/1000 km = 352 m
Now, circumference of circular field = 352 m
⇒ 2πr = 352 m
2 x (22/7) x r = 352
⇒ r = 56 m
Therefore, area of the field = πr2
= (22/7) x 56 x 56
= 8 x 22 x 56 m2
= 9856 sq m.