The cost of 5 kg of potatoes is £3.60 The cost of 1/2kg of carrots is 31p
Work out the total cost of 13 kg of potatoes and 2 1/2 kg of carrots.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

the arc length is found by finding the circumference of the full circle (2xpixradius) and then dividing by 4 to find just one quarter of the circle (90 degrees).