You didn't include the formula.
Given that there is no data about the mass, I will suppose that the formula is that of the simple pendulum (which is only valid if the mass is negligible).
Any way my idea is to teach you how to use the formula and you can apply the procedure to the real formula that the problem incorporates.
Simple pendulum formula:
Period = 2π √(L/g)
Square both sides
Period^2 = (2π)^2 L/g
L = [Period / 2π)^2 * g
Period = 3.1 s
2π ≈ 6.28
g ≈ 10 m/s^2
L = [3.1s/6.28]^2 * 10m/s^2 =2.43 m
I hope this helps you.
A similarity transformation is one or more rigid transformations (reflection, rotation, translation) followed by a dilation. When a figure is transformed by a similarity transformation, an image is created that is similar to the original figure.
Imma go with F just because I think it’s right
