7. It was the ......
who developed the 'foot' as their unit of length.
Answers
Answer:
Correct Question -
The circumference of two circle are in the ratio 2 : 3. Find the ratio of their areas.
Given -
Ratio of their circumference = 2:3
To find -
Ratio of their areas.
Formula used -
Circumference of circle
Area of circle.
Solution -
In the question, we are provided, with the ratios of the circumference of 2 circles, and we need to find the ratio of area of those circle, for that first we will use the formula of circumference of a circle, then we will use the formula of area of circles. We will be writing 1 equation in it too.
So -
Let the circumference of 2 circles be c1 and c2
According to question -
c1 : c2
Circumference of circle = 2πr
where -
π =
r = radius
On substituting the values -
c1 : c2 = 2 : 3
2πr1 : 2πr2 = 2 : 3
=
= [Equation 1]
Now -
Let the areas of both the circles be A1 and A2
Area of circle = πr²
So -
Area of both circles = πr1² : πr2²
On substituting the values -
A1 : A2 = πr1² : πr2²
=
=
= [From equation 1]
So -
=
The ratio of their areas is 4 : 9
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Hey there!
Dyfnwal Moelmud is known for the first usage of 'foot'. But it is also said that King Henry I of England, whose rule began in 1100, decided to standardize this unit of measure with his foot as the new standard unit of length.