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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                        View Hint View Answer Discuss in Forum Let the third side be x. 
 According to the question,
 x + 20 = 26Correct Option: ALet 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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                        View Hint View Answer Discuss in Forum Let length of rectangle = 5k 
 and breadth of rectangle = 3k
 According to the quecation,
 5k - 3k = 8
 Required area = Lenght x BreadthCorrect Option: CLet 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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                        View Hint View Answer Discuss in Forum Let length = 2x and breadth = x 
 According to the question,
 2x - x = 5
 ∴ Required perimeter = 2(2x + x)Correct Option: ALet 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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                        View Hint View Answer Discuss in Forum 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: BLet 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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                        View Hint View Answer Discuss in Forum 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: BThe 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.
 
	