When the radius of a circle is multiplied by a factor of 2, by what factor will the area of the circle change?

the area of a circle with radius 2 is times as big as the area of a circle with radius 1.

If the slope of one line equals the slope of another line then ? a) the two lines are intersecting lines b) the two lines are perpendicular lines c) the two lines are parallel lines d) the two lines always have very steep slopes

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Tell whether the two rates form a proportion