Q8 of 99 Page 269

If perimeter of a rhombus is 20 cm. and length of its one diagonal is 6 cm, then let us write by calculating the area of rhombus.

Given, perimeter of a rhombus is 20 cm. and length of its one diagonal is 6 cm


Side AB =


⟹ AB =


⟹ AB = 5cm


The diagonal AC =6cm


Hence, AO = 3cm


∠AOB = 90 ( the two diagonals of rhombus perpendicular bisected to each other)


Hence, OB2=AB2−AO2


⟹ OB2=52−32


⟹ OB = 4cm


∴ BD = 4×2


⟹ BD = 8cm


∴ Area of the Rhombus = ×8×6


= 24 sq.cm


More from this chapter

All 99 →
6

If the measure of two diagonals of a rhombus are 15 meter and 20 meter, then let us write by calculating its perimeter, area and height.

 7

If perimeter of a rhombus is 440 meter and distance between two parallel sides are 22 meter, let us write by calculating the area of shape of rhombus.

 9

The area of field shaped in trapezium is 1400 sq. dcm. If the perpendicular distance between two parallel sides are 20 dcm and the length of two parallel sides are in the ratio 3 : 4, then let us write by calculating the lengths of two sides.

 10

Let us write by calculating the area of regular hexagon field of which length of sides is 8 cm. [Hints: If we draw diagonals we get equal six equilateral triangles]