ABC is an acute-angled triangle with AB=10 cm, BC-13 cm and CA =14 cm. E and F are points on AB and AC respectively such that AE = AF =4 cm. The sector AEF of a circle with centre A is removed to leave the irregularly shaped region EBCF. (a) Show that angle CAB is 1.10 radians, correct to 3 significant figures. (b) Find the perimeter of region EBCF. t 0 10 20 X 275 440 ? Find the value of X when t = 20. 9. (a) The quantity X is increasing exponentially with respect to time t. The table below shows values of X for different values of t. (b) The quantity Y is decreasing exponentially with respect to time t, such that Y = 80e-0.021 20, giving your answer to 3 significant figures. 3 Find the value of t for which Y Rsin(- [2] [2] [3]