Adart is thrown at the board shown. it hits the board at a random point. find the probability that it will land in the shaded region. round to the nearest percent.

Question does not specify the size of the individual triangles.
IF all the the triangles are congruent, then the shaded area is one triangle out of four.
The probability of hitting the shaded area 
=area of shaded triangle / total area
= 1/4
(or 0.25)

The percent increase is 25%