Chapter 9: Perimeter and Area

Solution:-

From the question, it is given that

AC = 22 cm, BM = 3 cm DN = 3 cm and BM ⊥ AC, DN ⊥ AC

To find the area of quadrilateral ABCD, first, we have to find the area of ΔABC, and ΔADC Area of ΔABC = ½ × Base × Height

= ½ × 22 × 3

= 1 × 11 × 3

= 33 cm²

Area of ΔADC = ½ × Base × Height

= ½ × 22 × 3

= 1 × 11 × 3

= 33 cm²

Then,

Area of quadrilateral ABCD = Area of ΔABC + Area of ΔADC

= 33 + 33

= 66 cm²

Disclaimer:

Dropped Topics – 11.1 Introduction, 11.2 Squares and rectangles, 11.2.1 Triangles as parts of rectangles, 11.2.2 Generalising for other congruent parts of rectangles, 11.6 Conversion of units and 11.7 Applications.