In a standard deck of 52 cards, there are 4 suits: hearts, spades, diamonds, and clubs. Each suit has 13 cards.
To find the probability of picking a heart, we can use the formula for probability:
\[ \text{Probability of an event} = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}} \]
In this case:
- The number of favorable outcomes (number of hearts) is 13.
- The total number of possible outcomes (total number of cards) is 52.
So, the probability of picking a heart is:
\[ \text{Probability} = \frac{13}{52} \]
Now, we can simplify the fraction:
\[ \frac{13}{52} = \frac{1}{4} \]
Thus, the theoretical probability of Jaque picking a heart from the deck is:
\[ \boxed{\frac{1}{4}} \]