All the diagonals of the pentagon are drawn, forming a star inside it. How many triangles are there in the figure?

Sort by how many pentagon corners a triangle uses: 3 corners $\left(\genfrac{}{}{0ex}{}{5}{3}\right)=10$; 2 corners and 1 crossing point 20; 1 corner and 2 crossing points (the star tips) 5. Total $10+20+5=35$.