# Suspension Bridge

## Applying Parabolas in models

Belinda, a civil engineer, designs a model for the curved cable of a 6 m suspension bridge using the equation , where h metres is the height of the hanging cables above the road for a distance d metres from the left pillar.

What are the possible values for d? Why?

How could you determine the height of the pillars above the road without a graph?

How could you find the minimum height the cable reaches above the road?

## Extension

What would be the equations needed to add the support cables to the graph shown in the applet above? See if you can add them.

## Source

Greenwood, David Michael, Dave Robertson, Sara Woolley, Jennifer Goodman, and Jennifer Vaughan.

*Essential Mathematics for the Australian Curriculum Year 10*. 2nd ed. Essential Mathematics. Cambridge: Cambridge University Press, 2015. Electronic Format.