• Want to level up your HSC prep on those harder Maths questions?
    Register now for the BoS Trials (7th October)!

Rates of Change Question (1 Viewer)

Lukybear

Active Member
Joined
May 6, 2008
Messages
1,466
Gender
Male
HSC
2010
The altitude of a right-angled triangle is 6 cm and the base is increasing at a constant rate of 2cm/s. At what rate it the hypotenuse increasing when its length is 10 cm?

No idea how to do this question. But i did approach it. I tried using similar triangles but it didn't work out. Why?

Let length be y and base be x

At y=10
6/y = x/h
6/10 = x/h
x = 3/5 h
dx/dt = 3/5 dh/dt
thus dh/dt = 10/3 cm/s

The actual answer is 1.6
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top