Question

Given an isosceles trapezium $ABCD$ in order with $AB=6,CD=12$ and area $36$ sq units. Find the length of the side $BC$.

• A. $6$
• B. $5$
• C. $4.5$
• D. $5.5$

Answer 1

The correct option is B $5$

The trapezium can be divided in $3$ parts, a rectangle of $6$ units, $2$ equal triangles.
Let the height be $x$,
Area of trapezium $=$ Area of rectangle $+2$(Area of triangle)
$36=6\times x+2(\frac{1}{2}\times 3\times x)$ , base$=3$ units, the sides are equally divided.
$36=9x,$
$x=4units$,
$BC=5units$ (Pythagoras theorem)