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 2
Qstn# A-12 Prvs-QstnNext-Qstn
  • #12
    The altitude and the base of a triangular field are in the ratio 6 : 5. If its cost is ₹ 49,57,200 at the rate of ₹ 36,720 per hectare and 1 hectare = 10,000 sq. m, find (in metre) dimensions of the field,
    Ans : Total cost = ₹ 49,57,200
    Rate = ₹ 36,720 per hectare
    Total area of the triangular field = 4957200/36720 × 10000 m2
    = 1350000 m2
    Ratio in altitude and base of the field = 6 : 5
    Let altitude = 6x
    and Base = 5x
    ∴ Area = ½ × Base × Altitude
    ⇒ 1350000 = ½ × 5x × 6x
    ⇒ 15x2 = 1350000
    ⇒ x2 = 1350000/15
    ⇒ x2 = 90000
    = (300)2
    ∴ x = 300
    ∴ Base = 5x = 5 × 300 = 1500 m
    And Altitude = 6x = 6 × 300 = 1800 m