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on average, a person’s heart beats about 4.2×10^7times per year. there are about 7,600,000,000 people in the world. use this data to approximate the number of heartbeats for all the people in the world per year. expressing your answer in scientific notation in the form a×10^b, what are the values of a and b?

a=

b=

Acircle has a circumference of 2 pi cm. which statement about the circumference and area is true? a comparison of the area and circumference is not possible since the area cannot be determined. the numerical values of the circumference and area of the circle are equal. the numerical value of the circumference is greater than the numerical value of the area. the numerical value of the circumference is less than the numerical value of the area.

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60

Find the value of x for which line a is parallel to line b