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# In Fig. 9.38, ABCD is a square with AB = 15 cm. Find the area of the square BDFE.

**Solution:**

Given, ABCD is a __square__

AB = 15 cm

We have to find the __area of the square__ BDFE.

From the figure,

BD is the diagonal of the square ABCD.

__Diagonal of square__ = side × √2

= 15√2 cm

So, the length of the side of square BDFE = 15√2 cm

Area of square = (side)²

= (15√2)²

= (15)² × 2

= 225(2)

= 450 cm²

Therefore, the area of square BDFE is 450 cm².

**✦ Try This:** Each side of a square flower bed is 3m 90 cm long, It is extended by digging a strip 40 cm wide all around it. Find the area of the enlarged flower bed and also the increase in the area of the flower bed.

**☛ Also Check: **NCERT Solutions for Class 7 Maths Chapter 11

**NCERT Exemplar Class 7 Maths Chapter 9 Problem 84**

## In Fig. 9.38, ABCD is a square with AB = 15 cm. Find the area of the square BDFE.

**Summary:**

In Fig. 9.38, ABCD is a square with AB = 15 cm. The area of the square BDFE is 450 cm².

**☛ Related Questions:**

- In the given triangles of Fig. 9.39, perimeter of ∆ABC = perimeter of ∆PQR. Find the area of ∆ABC
- Altitudes MN and MO of parallelogram MGHK are 8 cm and 4 cm long respectively (Fig. 9.40). One side . . . .
- In Fig. 9.41, the area of ∆PQR is 20 cm² and area of ∆PQS is 44 cm². Find the length RS, if PQ is pe . . . .

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