Mensuration


  1. The area of a circle inscribed in a square of area 2m² is









  1. View Hint View Answer Discuss in Forum

    Using Rule 10 and 14,
    Side of square = √2 metre Radius of in-circle

    =
    2
    =
    1
    metre
    22

    Area of the circle = πr²
    = π ×
    1
    =
    π
    sq. metre
    22

    Correct Option: B

    Using Rule 10 and 14,
    Side of square = √2 metre Radius of in-circle

    =
    2
    =
    1
    metre
    22

    Area of the circle = πr²
    = π ×
    1
    =
    π
    sq. metre
    22


  1. Three coins of the same size (radius 1 cm) are placed on a table such that each of them touches the other two. The area enclosed by the coins is









  1. View Hint View Answer Discuss in Forum

    Using Rule 6 AND 17,

    Obviously, the triangle ABC will be equilateral.
    AB = BC = CA = 2 cm.
    Area of ∆ ABC

    =
    3
    × 2 × 2
    4

    = √3 cm²
    Then, area ‘A’ of the three sectors each of angle 60° in a circle of radius 1 cm.
    A = 3 ×
    60
    × π × 1 =
    π
    3602

    ∴ Area of the shaded portion
    = 3 -
    π
    cm².
    2

    Correct Option: B

    Using Rule 6 AND 17,

    Obviously, the triangle ABC will be equilateral.
    AB = BC = CA = 2 cm.
    Area of ∆ ABC

    =
    3
    × 2 × 2
    4

    = √3 cm²
    Then, area ‘A’ of the three sectors each of angle 60° in a circle of radius 1 cm.
    A = 3 ×
    60
    × π × 1 =
    π
    3602

    ∴ Area of the shaded portion
    = 3 -
    π
    cm².
    2



  1. Each side of a regular hexagon is 1 cm. The area of the hexagon is









  1. View Hint View Answer Discuss in Forum

    Area of regular hexagon =
    3√3
    × (side)²
    2

    =
    3√3
    × 1 =
    3√3
    cm²
    22

    Correct Option: A

    Area of regular hexagon =
    3√3
    × (side)²
    2

    =
    3√3
    × 1 =
    3√3
    cm²
    22


  1. An equilateral triangle of side 6 cm has its corners cut off to form a regular hexagon. Area (in cm2) of this regular hexagon will be









  1. View Hint View Answer Discuss in Forum

    Tricky approach


    Side of the regular hexagon =
    1
    × 6 = 2cm
    3

    ∴ Area of the hexagon =
    3√3
    2

    ∴ Area of the hexagon =
    3√3
    × 2 × 2 = 6√3 sq. cm.
    2

    Correct Option: C

    Tricky approach


    Side of the regular hexagon =
    1
    × 6 = 2cm
    3

    ∴ Area of the hexagon =
    3√3
    2

    ∴ Area of the hexagon =
    3√3
    × 2 × 2 = 6√3 sq. cm.
    2



  1. The ratio of the area of a regular hexagon and an equilateral triangle having same perimeter is









  1. View Hint View Answer Discuss in Forum

    Perimeter of regular hexagon = Perimeter of equilateral triangle.
    i.e. If a side of the regular hexagon be x units, then side of triangle = 2x units.

    ∴ Required ratio = 6
    3
    x² :
    3
    (2x)²
    44

    = 6 : 4 = 3 : 2

    Correct Option: C

    Perimeter of regular hexagon = Perimeter of equilateral triangle.
    i.e. If a side of the regular hexagon be x units, then side of triangle = 2x units.

    ∴ Required ratio = 6
    3
    x² :
    3
    (2x)²
    44

    = 6 : 4 = 3 : 2