SOLUTION: a field is in the shape of a trapezium having parallel sides 90m and 30m. These sides meet the third side at the right angle. The length of the forth side is 100m. Find Area(using

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: a field is in the shape of a trapezium having parallel sides 90m and 30m. These sides meet the third side at the right angle. The length of the forth side is 100m. Find Area(using       Log On

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Question 782720: a field is in the shape of a trapezium having parallel sides 90m and 30m. These sides meet the third side at the right angle. The length of the forth side is 100m. Find Area(using heron's formula).
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
parallel sides are 90 & 30
if you draw a perpendicular from the smaller side
itdivides the opposite side into 30 and 60
there are two shapes one is a rectangle and other is a right triangle
the right triangle has hypotenuse of 100 and one side as 60
so other side =
sqrt(100^2-60^2)= 80
the there sides of triangle are
60,80 and 100
herons formula
area = sqrt%28s%28s-a%29%28s-b%29%28s-c%29%29
where s= 1/2 the perimeter
s= (60+80+100)/2
=120

area = sqrt%28120%28120-60%29%28120-80%29%28120-100%29%29
= 2400
area of rectangle = 30 * 80
=2400
area of trapezium = area of triangle + area of rectangle
=2400 +2400
=4800 sq.m