Area and Perimeter


  1. The area of a trapezium is 384 sq.cm2. If its parallel sides are in ratio 3 : 5 and the perpendicular distance between them be 12 cm, The smaller of parallel sides is ?









  1. View Hint View Answer Discuss in Forum

    Let the sides of trapezium be 5k and 3k, respectively

    According to the question,
    (1/2) x [(5k + 3k) x 12] = 384

    Correct Option: B

    Let the sides of trapezium be 5k and 3k, respectively

    According to the question,
    (1/2) x [(5k + 3k) x 12] = 384
    ⇒ 8k = (384 x 2)/12 = 64
    ⇒ k = 64/8 = 8 cm

    Length of smaller of the parallel sides = 8 x 3 = 24 cm


  1. The circumference of a circle is 25 cm. Find the side of the square incribed in the circle.











  1. View Hint View Answer Discuss in Forum

    Circumference of the circle = 2πr = 25
    ⇒ r = 25 / (2π)

    According to the formula,
    Side of inscribed square = r√2

    Correct Option: A

    Circumference of the circle = 2πr = 25
    ⇒ r = 25 / (2π)

    According to the formula,
    Side of inscribed square = r√2
    = 25 / (2πr x √2)
    = 25 / (π√2 ) cm



  1. If area of a square is 64 sq cm, then find the area of the circle formed by the same perimeter.











  1. View Hint View Answer Discuss in Forum

    Area of square = 64 sq cm
    (Side)2 = 64
    ∴ Side = √64 = 8 cm


    According to the question,
    ⇒ 2πr = 4 x 8
    ⇒ r = (4 x 8)/2π

    Correct Option: C

    Area of square = 64 sq cm
    (Side)2 = 64
    ∴ Side = √64 = 8 cm


    According to the question,
    ⇒ 2πr = 4 x 8
    ⇒ r = (4 x 8)/2π
    ⇒ r = 16/π

    ∴ Area of the circle
    = π x (16/π) x (16/π) sq cm
    = 256/π sq cm.


  1. The side of a square is 5 cm which is 13 cm less than the diameter of a circle. What is the approximate area of the circle ?











  1. View Hint View Answer Discuss in Forum

    Diameter of the circle = 13 + 5 = 18 cm
    ∴ Radius = Diameter/2 =18/2 = 9 cm
    Area of the circle = πr2 = (22/7) x 92

    Correct Option: D

    Diameter of the circle = 13 + 5 = 18 cm
    ∴ Radius = Diameter/2 =18/2 = 9 cm
    Area of the circle = πr2 = (22/7) x 92
    = (22 x 81)/9
    = 1782/7
    = 254.57 sq cm
    = 255 sq cm



  1. The ratio of the area of the circumcircle and the incircle of a square is









  1. View Hint View Answer Discuss in Forum

    Ratio of the areas of the circumcircle and incircle of a square
    = [(Diagonal)2π] / [(Side)2π]

    Correct Option: A

    Ratio of the areas of the circumcircle and incircle of a square
    = [(Diagonal)2π] / [(Side)2π]
    = [(Side x √2)2] / (Side)2 = 2/1 or 2 : 1