When giving physical quantities you cannot omit the units. (an angle of 10 what). You cannot solve the problem fully because you are missing the length of the pendulum.
You cannot use any kinematic relations because the expression of the period depends on the assumption that angles of rotation remain small.
You will have to use the energy conservation principle. Assuming that the mass was released with 0 initial kinetic energy, the kinetic energy at the lower point (angle 10 degrees) is equal to the change in potential energy between the release point and the point where the mass is.
(1/2)mv^2=delta Ep= Ep(30 deg)-Ep(10 deg)
Once you calculate the potential energy (see screen capture) difference you will see that it is proportional to m*g, so the mass will cancel out.
Your turn: Calculate the potential energy difference between the positions at 30 deg and 10 deg, equate the result with the kinetic energy and solve for v^2, and hence for v the tangential velocity.
×