# Thread: Want help to draw a circle in a graph via point data and axis in Excel

1. Member
Join Date
Feb 2012
Posts
9

## Want help to draw a circle in a graph via point data and axis in Excel

I am working with more circles and I want to draw a circle on my graphs using a data point (x,y) values to make the circles. Now if I was using a compass, I would set my compass point on the x-axis at the x-value and then draw a circle with radius (y) around that point ensuring that I intercept the x-axis at distance (x + y), (x - y) and point (x,y). I am trying to figure out if there is someway I can conveniently construct these circles in excel rather than printing out the graph and then hand-drawing them over the plotted data points.

2. Member
Join Date
Aug 2011
Posts
700

## Re: Want help to draw a circle in a graph via point data and axis in Excel

I haven't done Mohr's Circle since gradual school. Knowing the (Xc,Yc) coordinates of the circle's center, and the circle's radius R, you can calculate points of the circle, then plot the points on the chart: Put Xc, Yc, and R into B1, C1, and D1. Enter 0 in A3 and 10 in A4. Select A3:A4, then drag the black square at the bottom right corner of the selection downward until you have filled from 0 to 360 in steps of 10 (down to A39). In B3 enter this formula:
• =\$B\$1+\$D\$1*COS(A3*PI()/180). In C3 enter this formula
• =\$C\$1+\$D\$1*SIN(A3*PI()/180). Select B3:C3, and double click on the little
there will be a black square on the bottom right corner of the selection, which will fill these formulas down to row 39. Select & copy B3:C39, select the chart, and use Paste Special to add this data to the chart as a new series.

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