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If D, E and F are the mid points of BC, ...

If D, E and F are the mid points of BC, CA and AB respectively of the `triangle ABC` then the ratio of aria parallelogram DEFB and area of the trapezium CAFD is ,

A

`2 : 3`

B

`3 : 4`

C

`1 : 2`

D

`1 : 3`

Text Solution

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The correct Answer is:
To find the ratio of the area of parallelogram DEFB to the area of trapezium CAFD in triangle ABC, we can follow these steps: ### Step 1: Understand the Triangle and Midpoints Let triangle ABC have vertices A, B, and C. The midpoints of sides BC, CA, and AB are D, E, and F respectively. ### Step 2: Identify Areas of Smaller Shapes When we connect the midpoints, we form smaller triangles and a parallelogram within triangle ABC. The triangles formed are AEF, BDF, and CDE. The area of triangle ABC can be divided into four smaller areas: triangle AEF, triangle BDF, triangle CDE, and parallelogram DEFB. ### Step 3: Calculate Areas of Smaller Triangles Since D, E, and F are midpoints, each of the triangles AEF, BDF, and CDE will have equal areas. Let the area of each of these triangles be x. Therefore, the area of triangle ABC is: \[ \text{Area of } ABC = AEF + BDF + CDE = x + x + x = 3x \] ### Step 4: Area of Parallelogram DEFB The area of parallelogram DEFB can be calculated as follows: \[ \text{Area of } DEFB = \text{Area of } ABC - (\text{Area of } AEF + \text{Area of } CDE) = 3x - (x + x) = 3x - 2x = x \] ### Step 5: Area of Trapezium CAFD The area of trapezium CAFD can be calculated as: \[ \text{Area of } CAFD = \text{Area of } ABC - \text{Area of } BDF = 3x - x = 2x \] ### Step 6: Calculate the Ratio Now, we can find the ratio of the area of parallelogram DEFB to the area of trapezium CAFD: \[ \text{Ratio} = \frac{\text{Area of } DEFB}{\text{Area of } CAFD} = \frac{x}{2x} = \frac{1}{2} \] ### Conclusion Thus, the ratio of the area of parallelogram DEFB to the area of trapezium CAFD is \( \frac{1}{2} \).
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