Favourite fruit as voted by the class is represented in the pie chart given below. The number of students who like oranges is 30.
How many students like pineapples?

The correct option is B 45
In the given pie chart, the central angle of the sector corresponding to oranges is ${90}^{\circ }$, and it is given that 30 students like oranges.

Hence, ${90}^{\circ }$ represents 30 students. We know that the full circle (${360}^{\circ }$) represents the entire class.
$⟹\text{Total number of students}=\frac{{360}^{\circ }}{{90}^{\circ }}\times 30=120.$

Note that the central angle of the sector corresponding to pineapples is ${135}^{\circ }.$
$\therefore \text{Number of students who like pineapples}=\frac{{135}^{\circ }}{{360}^{\circ }}\times 120=45.$