Geometric probability is the ratio of the favorable measure (area or length) to the total measure.
Geometric probability formula
$$P(A)=\frac{s}{S}$$
where,
s— measure of the favorable region (length, area, or volume), where a randomly chosen point/object must fall for the event to occur;
S— total measure (length, area, or volume) of the region over which the selection is made.
