Kayla is in grade 10. She wants to have longer hair for her graduation. Her hair grows at a constant. rate. If it is 24.0 cm long today, in 30 days it will be 25.2 cm long.

Question

Sketch a straight line graph representing the rate at which Kayla's hair grows.

*What is the slope of the line and what ages it represent?

• What is the y-intercept and what does it mean?

• Write an equation in slope-intercept form that describes how Kayla's hair length, L, in centimeters, grows each day, d.

• Predict the length of Kayla's hair at graduation if she does not get it trimmed over the next two years

Answer 1

L= 24+1.2d/30

L=24+.04d

or

y=.04x +24 on x and y axes

slope =.04= how much her hair grows in one day

y intercept = 24 = hair length today

in 2 years =2(365)= 730 days

L=24+.04(730)=24+29.2=53.2 cm