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
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=
The height of parallelogram is equal to radius of circle
Height of parallelogram =r cm
Area of parallelogram=
Area of parallelogram=
Therefore, the area of circle is given by the formula =
Hence, option A is true.