Please only graph and explain how you graphed, thank you(please dont use desmos)

3. A group of students decided to study the sinusoidal nature of tides. Values for the depth of the water level were recorded at various times. At t=2 hours low tide was recorded at a depth of 1.8 m. At t=8 hours, high tide was recorded at a depth of 3.6 m. (a) Sketch the graph of this function (b) Write an equation expressing distance in terms of time (c) Give the depth of water at t=21 hours