Question 1191626
OP is equal to 2.8 cm.
OT is equal to 5.5.
right triangle OPT is formed with OT as the  hypotenuse and OP as one of the legs.
PT is the other leg, which is also the tangent line to the circle.
OPT is the right angle.
let OP = x and PT = y and OT = z.
by pythagorus, z^2 = x^2 + y^2
replace x with 2.8 because that's the length of OP, and replace z with 5.5 because that's the length of OT, and you get 2.8^2 + y^2 = 5.5^2.
solve for y^2 to get y^2 = 5.5^2 - 2.8^2 = 22.41.
solve for y to get y = sqrt(22.41) = 4.733920151.
that's the length of PT which is the tangent.
that should be your answer.
you can say it's sqrt(22.41) or you can say it's 4.733920151.
you can round 4.733920151 as required, if that's the way  they want to see the answer.
the answer depends on the fact that the tangent to a circle is perpendicular to the radius of the circle at the point of tangency.
here's a reference on tangent to a circle.
<a href = "https://www.cuemath.com/geometry/tangent/" target = "_blank">https://www.cuemath.com/geometry/tangent/</a>
let me know if you have any questions or concerns.
theo