Question

Below is the justification for the formula for area of a circle. Which word, when placed in the blank best completes this argument?

Answer 1

Answer:

The correct answer is option A.  r

Step-by-step explanation:

From the figure we can see a circle and a parallelogram.

The circle is divided into a small sectors and these sector then arranged into a parallelogram.

The base of the parallelogram is half the circumference.

The height of parallelogram is equal to the radius of the given circle. Here radius is 'r'.

Therefore the correct answer is option A.   r

Answer 2

Answer:

A. r

Step-by-step explanation:

We are given that justification for the formula of area of a circle.

We have to fill the right word in the blank which make best completes this argument

Let the radius of circle =r cm

The circumference of circle ==2$\pi r$

Circle divided into number of sector of equally sized and the sector can be re arranged in the form of a shape which is approximately  a parallelogram.

The base of parallelogram is equal to half of circumference

Base of parallelogram=$\pi r$

The height of parallelogram is equal to radius of circle

Height of parallelogram =r cm

Area of parallelogram=$base\times height$

Area of parallelogram=$\pi\timesr\times r=\pi r^2$

Therefore, the area of circle is given by the formula =$\pi r^2$

Hence, option A is true.