Answer:
4
Step-by-step explanation:
We can observe that chord AD and DB is the radius of the circle D. Thus they are equal, and
AD = TB + DT
5 = 2 + DT
DT = 3
Using the Pythagorean theorem, AT is equal to,
AT² = AD² - DT²
AT² = (5)² - (3)²
AT² = 16
AT = 4
