Find the number at the position of ?

Step 1: Analyze the pattern in the first two triangles.
We need to find a consistent mathematical relationship between the numbers at the vertices (top, bottom left, bottom right) and the number inside each triangle.

Let's denote:

• Top vertex as $T$
• Bottom left vertex as $BL$
• Bottom right vertex as $BR$
• Inside number as $I$

For the first triangle:
$T = 1$
$BL = 6$
$BR = 20$
$I = 3$

Let's test a possible relationship: $(BL \times I) + T = BR$.
$(6 \times 3) + 1 = 18 + 1 = 19