HomeLearn Fast select Course
Show Unit/ChapterChange UnitChange SubjectLast Menu
ICSE-VIII-Mathematics

20: Area of Trapezium and a Polygon Class 8 Maths

with Solutions - page 5
Qstn# C-7 Prvs-QstnNext-Qstn
  • #7
    The diagonals of a rhombus are 18 cm and 24 cm. Find: (i) its area ; (ii) length of its sides. (iii) its perimeter;
    Ans : (i) Diagonal of rhombus are 18 cm and 24 cm.
    area of rhombus = 1/2 ×Product of diagonals
    = 1/2 × 18 × 24
    = 216 cm2 (ii) Diagonals of rhombus bisect each other at right angles.

    ∴ OA = ½ × 24 = 12 cm OB =1/2 × 18 = 9 cm
    In right ∠d ΔAOB
    ∴ Side of rhombus = 15 cm (iii) Perimeter of rhombus = 4 × side
    = 4 × 15
    = 60 cm
    (i) 216 cm2(ii) 15 cm(iii) 60 cm
  • #7-i
    its area ;
    Ans : Diagonal of rhombus are 18 cm and 24 cm.
    area of rhombus = 1/2 ×Product of diagonals
    = 1/2 × 18 × 24
    = 216 cm2
  • #7-ii
    length of its sides.
    Ans : Diagonals of rhombus bisect each other at right angles.

    ∴ OA = ½ × 24 = 12 cm OB =1/2 × 18 = 9 cm
    In right ∠d ΔAOB
    ∴ Side of rhombus = 15 cm
  • #7-iii
    its perimeter;
    Ans : Perimeter of rhombus = 4 × side
    = 4 × 15
    = 60 cm
    (i) 216 cm2(ii) 15 cm(iii) 60 cm