two parallel sides of a trapezium are 60cm and 77cm and other sides are 25cm and 26cm find the area of trapezium.
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Answers
Answer:
1644 cm²
Step-by-step explanation:
Let ABCD be the trapezium in which AB || CD and BF ⊥ DC.
∴ AE = BF and AB = EF = 60 cm.
Let DE = 'x' cm and FC = 77 - (60 + x) = 17 - x.
(i) In ΔAED:
AE² = AD² - DE²
= 625 - x²
(ii) In ΔBFC,
BF² = (BC)² - (FC)²
= (26)² - (17 - x)²
= 676 - (289 + x² - 34x)
= 676 - 289 - x² + 34x
= 387 - x² + 34x
But AE = BF
On Squaring both sides, we get
⇒ AE² = BF²
⇒ 625 - x² = 387 - x² + 34x
⇒ 625 - x² - 387 + x² - 34x = 0
⇒ 238 - 34x
⇒ x = 7.
∴ AE = √625 - 49
= √576
= 24 cm
∴ Area of trapezium ABCD = (1/2) * AE * (AB + CD)
= (1/2) * 24 * (60 + 77)
= 1644 cm²
Therefore, Area of trapezium = 1644 cm².
Hope it helps!