thank you plato!
however i find using plato's secant theorem being the easier:
(-10 +/- sq.root 82) / 2
and since we need a positive value we do:
(-10 + sq.root 82) / 2
and add the 5cm radius to get OC
=sq. root 205 as soroban said
Thanks for the help!
That is also my method except that I didnít use trigonometry. By Pythagorasí theorem on triangle ODA, OD = = 3 cm. By Pythagorasí theorem on triangle ODC, OC = cm.
You made a mistake there; it should be 820, not 82. Itís also easier to make mistakes with your calculations using the secant method. My recommendation: use the method that Soroban and I used.