If an individual homozygous dominant for widow's peak has a child with an individual heterozygous for widow's peak, what is the chance that the child will have a widow's peak?

100%

Explanation:

Let PP represent homozygous dominant trait for widow's peak &

Let Pp represent  an individual heterozygous for widow's peak.

If both traits cross together;  the chance that the child will have a widow's peak = ???

i.e PP × Pp

   |     P     |     P

P  |    PP   |     PP        

p  |    Pp   |     Pp

The progeny are: ( PP, PP, Pp, Pp)    

When a trait is dominant, only one allele is required for the trait to be observed. A dominant allele will mask a recessive allele, if present.

From our question, one  parent is homozygous dominant (PP) and the other is  heterozygous (Pp):  therefore  all their offspring will be  two homozygous dominant (PP) and two heterozygous  (Pp) and they will all possess a widow’s peak.

Therefore, the chance that a child will have a widow's peak = 100%