How many 7-digit phone numbers can be formed if the first digit cannot be 0 and repetition of digits is allowed?

7,000,000

9,000,000

181,400

none of the above

At school there are 526 students and 263 are girls about how likely is it that a randomly chosen student will be a boy

What effect would doubling all the dimensions of a triangular pyramid have on the volume of the pyramid? explain your reasoning.

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)