Question: Points A, B, C and D divide the circumference of a circle in the ratio 1:2:3:4. Find the angles of the cyclic quadrilateral ABCD in radians.

The answers are 3pi/10, pi/2, 7pi/10 and pi/2.

But I don't really understand because what I calculated are 36, 72, 108, 144 degrees respectively. [using 360/(1+2+3+4) and multiply the ratio]. How can I get the above answer?? Thanks

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