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ICSE-VIII-Mathematics

20: Area of Trapezium and a Polygon Class 8 Maths

with Solutions -
Qstn# A-3 Prvs-QstnNext-Qstn
  • #3
    The sides of a triangle are 16 cm, 12 cm and 20 cm. Find : (i) area of the triangle ; (ii) height of the triangle, corresponding to the largest side ; (iii) height of the triangle, corresponding to the smallest side.
    Ans : Sides of ∆ are
    a = 20 cm
    b = 12 cm
    c = 16 cm
    S = (a + b + c)/2
    = (20 + 12 + 16)/2
    = 48/2
    = 24

    AD is height of ∆ corresponding to largest side.
    ∴ ½ × BC × AD = 96
    ⇒ ½ × 20 × AD = 96⇒ AD = (96 × 2)/20
    ⇒ AD = 9.6 cm
    BE is height ∆ corresponding to smallest side.
    ∴ ½ × AC × BE = 96
    ⇒ ½ × 12 × BE = 96
    ⇒ BE = (96 × 2)/12
    ⇒ BE = 16 cm (i) 96cm2(ii) 9.6 cm(iii) 16 cm
  • #3-i
    area of the triangle ; (ii) height of the triangle, corresponding to the largest side ; (iii) height of the triangle, corresponding to the smallest side.
    Ans : 96cm2(ii) 9.6 cm(iii) 16 cm