Chapter 9: Perimeter and Area

Solution:-

In area of parallelogram BCEF is 35cm² where ACDF is a rectangle.

From the figure FE = FD – AB

= 10 – 3

= 7 cm

Then, area of parallelogram = base × height

= FE × CE [CD = CE]

= FE × CD

= 7 × 5

= 35 cm²

Solution:-

To find area, any side of a parallelogram can be chosen as base of the parallelogram.

Solution:-

Perpendicular dropped on the base of a parallelogram from the opposite vertex is known as the corresponding height/altitude of the base.

Solution:-

The distance around a circle is its circumference.

Solution:-

Ratio of the circumference of a circle to its diameter is denoted by symbol π.

Solution:-

If area of a triangular piece of cardboard is 90 cm², then the length of altitude corresponding to 20 cm long base is 9cm.

We know that, area of triangle = ½ × base × height

90 = ½ × 20 × height

Height = 9 cm

Solution:-

Value of π is (22/7)=3.14 approximately.

Solution:-

Circumference ‘C’ of a circle can be found by multiplying diameter ‘d’ with π.

We know that, circumference of circle when radius is considered = 2 πr

When diameter is considered = πd

Solution:-

Circumference ‘C’ of a circle is equal to 2π × r.

Solution:-

1 m² = 10000 cm².

We know that, 1 m = 100 cm

1 m² = 100² cm²