Determine the acceleration of gravity for the terrain where a mathematical pendulum with a length of 99.4 cm

Determine the acceleration of gravity for the terrain where a mathematical pendulum with a length of 99.4 cm makes 40 oscillations in 80 s.

find the oscillation period T = t / N => T = 2c. Next, we transform the formula for the period of the mathematical pendulum into the form we need => T = 2П (square root of (l (pendulum length) / g (free fall acceleration)) => g = (4 П ^ 2 l) / T ^ 2 = > g = 9.81 m / s ^ 2