Question

In the diagram, CD = 15 and CF = 39. If line DF is tangent to point C, then DF = ?

Answer 1

I hope this helps you


DF^2+DC^2=FC^2



DF^2+15^2=39^2


DF^2=39^2-15^2


DF^2=24.54


DF=36

Answer 2

DF^2 = 39^2 - 15^2 = 1296
DF = square root of 1296 = 36