Mathematics
In the adjoining figure, AB || DC and AB ≠ DC. If the diagonals AC and BD of the trapezium ABCD intersect at O, then which of the following statements is not true ?
area of △ABC = area of △ABD
area of △ACD = area of △BCD
area of △OAB = area of △OCD
area of △OAD = area of △OBC

Theorems on Area
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Answer
We know that,
Triangles on the same base and between same parallel lines are equal in area.
Hence,
⇒ area of △ABC = area of △ABD …….. (1)
⇒ area of △ACD = area of △BCD
From figure and eqn. (1),
area of (△AOB + △OAD) = area of (△AOB + △OBC)
⇒ area of △OAD = area of △OBC.
Hence, Option 3 is the correct option.
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Related Questions
The mid-points of the sides of a triangle along with any of the vertices as the fourth point make a parallelogram of area equal to
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In the adjoining figure, ABCD is a trapezium with parallel sides AB = a cm and DC = b cm. E and F are mid-points of the non-parallel sides. The ratio of area of ABFE and area of EFCD is
a : b
(3a + b) : (a + 3b)
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Consider the following two statements:
Statement 1: The line segment joining the mid-points of a pair of opposite sides of a parallelogram divides it into two equal parallelograms.
Statement 2: Diagonals of a parallelogram divide it into four triangles of equal area.
Which of the following is valid?
Both the statements are true.
Both the statements are false.
Statement 1 is true, and Statement 2 is false.
Statement 1 is false, and Statement 2 is true.
Assertion (A): Area of trapezium = (sum of parallel sides) x height.
Reason (R): A parallelogram and a rectangle on the same base and between the same parallel lines are equal in area.
Assertion (A) is true, Reason (R) is false.
Assertion (A) is false, Reason (R) is true.
Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct reason for Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct reason (or explanation) for Assertion (A).