Question for the Math guys

[UKSBD]

If I am working out the length based on gradient does it give me the length of the going or the length of the slope?

ie.

Height = 1m
Gradient = 1:15
Length = H x G = L = 15m

Is that 15m the measurement of the going or the measurement of the slope (hypotenuse) ?

 

[AllUpHere]

A 1 in 15 slope goes up 1m in 15m, so it has to be the length of the going.

Edit. The more I think about it, the less sure I am. Wait for better answers.

 

[fisicx]

Length along the ground.

To get the length of the slope good old Pythagoras need to get involved.

 

[UKSBD]

Length along the ground.

To get the length of the slope good old Pythagoras need to get involved.

Yeah I can use a calculator for that, it's knowing which was the correct sum to use was the problem

 

[UKSBD]

Edit. The more I think about it, the less sure I am. Wait for better answers.

I've been working in gradients for nearly 20 years but have never been 100% sure whether it was the going or the hypotenuse.

Always assumed it was the going, but when someone asked me, it got me thinking again.

 

[japancool]

1:15 means it goes up 15cm for every 1m in ground length (called the "run").

So a rise of 1m means 1/0.15 = run length of 6.67m, and the hypotenuse is 6.74m.

 

[UKSBD]

I've always treated a1 15 gradient as,
If it is 1m high the run is 15m hypotenuse 15.03

 

[fisicx]

I've always treated a1 15 gradient as,
If it is 1m high the run is 15m hypotenuse 15.03

Yes that is correct. The units in the ratio have to be the same. 1:15 in metres, cm, cubits, rice puddings or whatever. You can’t have 1m and 15cm

 

[japancool]

You can’t have 1m and 15cm

Sure you can. 15cm is 0.15m.

 

[UKSBD]

Where gradients are concerned it is 1 in 15 so the units should be the same.

 

[fisicx]

Where gradients are concerned it is 1 in 15 so the units should be the same.

Correct. It’s a ratio not a measurement.

 

[fisicx]

Sure you can. 15cm is 0.15m.

Yes, but the ratio would then be 1:0.15 or 100:15

You can mix units in a ratio.

 

[shopomatix]

Please tell me your not a flat earther