Answer: The circumference of the circle is 53.38 cm.
Step-by-step explanation:
Circumference of the circle is the distance around the circle.
Formula used:
Where,
C is circumference of circle
r is radius of circle
Given:
Radius of circle = 8.5 cm
Now putting all the given values in the above formula, we get:
Therefore, the circumference of the circle is 53.38 cm.
Answer:
The world population at the beginning of 2019 will be of 7.45 billion people.
Step-by-step explanation:
The world population can be modeled by the following equation.
In which Q(t) is the population in t years after 1980, in billions, Q(0) is the initial population and r is the growth rate.
The world population at the beginning of 1980 was 4.5 billion. Assuming that the population continued to grow at the rate of approximately 1.3%/year.
This means that
So
What will the world population be at the beginning of 2019 ?
2019 - 1980 = 39. So this is Q(39).
The world population at the beginning of 2019 will be of 7.45 billion people.