News1 min ago
percentage of a circle
Evening all. Got bit of a problem. Imagine an LPG tank the shape of an upright spare wheel - I need to draw a line across the face where an 80% level would theoretically be. The answer must be simple maths...
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Bit involved, but here we go.
You know the radius of the wheel, so area = pi * r^2
Work out 20% of this area (call it X)
Use this link http://www.mathwords.com/a/area_segment_circle.htm
to work out theta (Thats the thing that looks like an 0 with a line through it)[Area is X from above and you know radius r]
Distance S from centre of circle to edge of chord is
S = r * cos(theta/2)
r-S = the distance down from the top of the circle that you need to draw your line.
Hope that works!