What have you tried? The documentation is full of examples you could reuse. Especially take a look at ComponentMeasurements.
i = Import["https://wolfr.am/69kpZh7D"];
bi = Binarize[i]
cm = ComponentMeasurements[bi, hd = {"Centroid", "Count", "EquivalentDiskRadius"}];
TableForm[cm[[All, 2]], TableHeadings -> {cm[[All, 1]], hd}]
Show[i, Graphics[{Red, Thick, Circle[#[[1]], #[[2]]] & /@ cm[[All, 2, {1, 3}]]}]]
