Given:
.
To find:
The value of r.
Solution:
We have,
.
We know that the radius is perpendicular to the tangent at the point of tangency
AD is the tangent and CD is the radius. So, CD is perpendicular to AD at point D, i.e., .
Using Pythagoras theorem, we get
On further simplification, we get
Therefore, the value of r is 9.
Answer:
His brother will take 3.5 hours or hours to mow 21 lawns
Step-by-step explanation:
Given:
His brother mows 6 lawns in an hour.
To find the time his brother takes to mow 21 lawns.
Solution:
We will unitary method to find the time he will take to mow 21 lawns.
If 6 lawns are mowed in 1 hour
So, 1 lawn will me mowed in = hours.
Thus 21 lawns will be mowed in = hours.
Thus, his brother will take 3.5 hours or hours to mow 21 lawns