ΔCAD and ΔBCD is similar triangles
The proportions of corresponding sides are the same.
CD/AD = BD/CD
CD² = AD × BD
Plug the numbers to the formula above to find the value of x
CD² = AD × BD
x² = 24 × 5
x² = 120
x² = 4 × 30
x = √4 × √30
x = 2√30
The answer is second option