by what percent will the product of two numbers decrease if one of by 75% and the other is decreased by 25%

The circumference of a circle is 5 pi cm. what is the area of the circle?

The vertex of this parabola is at (-2,-3). when the x-value is -1, the y-value is -5. what is the coefficient of the squared expression in the parabola's equation?

Which of these numbers of simulations of an event would be most likely to produce results that are closest to those predicted by probability theory? 15, 20, 5, 10