The parallel sides of a trapezium are 40 cm and 20 cm. If its non-parallel sides are both equal, each being 26 cm,
find the area of the trapezium.
Answers
Area of trapezium is
1/2*sum of parallel sides *height
1/2 *40 +20 *24
1/2*60*24
30*24
=720
The equal sides = 26 cm.
The distance between the parallel sides = [26^2-{(40–20)/2}^2]^0.5
= [676–10^2]^0.5
= (676–100)^0.5
= 576^0.5
= 24 cm.
Area of trapezium = (40+20)*24/2 = 720 sq cm. Answer.
Given:
The parallel sides of trapezium = 40cm and 20cm.
The non-parallel sides of trapezium = 26cm = 26cm.
To Find:
The area of the trapezium.
Solution:
Assume a trapezium ABCD.
where, ABIICD, AD = BC, AB = 20cm, BC = 26cm, CD = 40cm, and DA = 26cm.
Now, Let AE and BF be the perpendiculars drawn on DC.
Consider triangle DAE, ∠A =90°,
By Pythagoras theorem,
H² = P² + B².
Here, H = AD = 26cm and B = DE = 10cm.
so, P² = 26² - 10².
P² = 676 - 100.
P² = 576cm².
P = AE = 24cm.
Now, By the area of the trapezium,
Area of trapezium = 1/2 × sum of parallel sides × distance between the parallel sides.
Area of trapezium ABCD = 1/2 × (AB + CD) × AE.
Area of trapezium ABCD = 1/2 × (20+40) × 24.
Area of trapezium ABCD = 1/2 × 60 × 24.
Area of trapezium ABCD = 720cm².
Hence, The area of trapezium ABCD is 720cm².