Question

Look at attached image please

So it says “the cost of building a light house is proportional to the cube of its height ,h”

And then follows on to the page I’ve shared

Does anyone know what to do

Answer 1

• X=20
• Y=40
• Z=60

We need ratio

`\\ \tt\hookrightarrow X:Y:Z=20:40:60=1:2:3`

#2

`\\ \tt\hookrightarrow (√(3)(√(3)+√(2)))/(3-2)`

`\\ \tt\hookrightarrow 3+√(6)`

#b

`\\ \tt\hookrightarrow (√(5)+2√(2)(2√(5)+√(2)))/(20-2)`

`\\ \tt\hookrightarrow (14+5√(10))/(18)`

#15

• y=√x

Graph attached