About `3.2 x 10^{8}` people live in the United States. About `3.9 x 10^{7}` people live in Canada.

And about `1.1 x 10^{8}` people live in Mexico.

About how many people live in all three countries altogether?

Which one ? is the answer and how to find this answer

Circle a has a diameter of 7 inches, a circumference of 21.98 inches, and an area of 38.465 square inches. the diameter of circle b is 6 inches, the circumference is 18.84 inches, and the area is 28.26 square inches. part a: using the formula for circumference, solve for the value of pi for each circle. (4 points) part b: use the formula for area and solve for the value of pi for each circle. (4 points)

Aright triangle has an area of 21 m2. the dimensions of the triangle are increased by a scale factor of 4. what is the area of the new triangle