There are 52 cards in a standard deck, and 4 suits. There is one 9 per suit, so 4 cards, plus one 10 per suit, so 8 cards. 8 cards divided by 52 cards in a deck is 0.15384615 or 0.154.
I honestly don’t know. But the square in the bottom of the triangles indicate that it is a right triangle equaling 90 degrees. You can try using that along with other knowledge of right triangles you have. Could you possibly use Pythagorean theorem also?
