Sorry about the handwriting! For (a), given that all points listed are on the circle, and that the radius of the circle is 7cm, we can conclude that all 3 triangles we’ve created are identical isosceles. For (c), consider triangle AOE as listed, where OE is a line perpendicular to AC. Simply use trigonometry to calculate the length of either AE or EC. Since AE=EC and AE+EC gives us the value for AC, we can find the length of this chord. For (dii), simply subtract the area of triangle AOC from sector AOC to find the area of segment ADC. Be careful with differentiating between degrees and radians, and be sure to leave your answers in an appropriate format where necessary. Hope this helps!