Help please need answers for 3 & 4 .

The graph shows the distance y, in inches, a pendulum moves to the right (positive displacement) and to the left (negative displacement), for a given number of seconds x. how many seconds are required for the pendulum to move from its resting position and return? enter your answer in the box.

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

In the diagram, the ratios of two pairs of corresponding sides are equal to prove that almn - axyz by the sas similarity theorem, it also needs to be shown that x 6 z un z zz un = 2x zləzz lezy