The diagram shows a circle of radius 1 contained in a square. If the area of the circle equals x% of the area of the square, then what is x rounded to the nearest integer?

Area of square  with a side of 2r  = 2(1)  = 2  = 2^2   = 4

Area of circle =  pi ( 1)^2  =  pi

x =  pi / 4   ≈  .79   =  79%

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."