Hey there!
The answer is 110.5 square mm.
The formula for a triangle is base times height divided by two. So, we take the base (17) times the height (13) divided by two (2):
[tex]\frac{17*13}{2}[/tex]
[tex]\frac{221}{2}[/tex]
[tex]110.5[/tex]
Have a super awesome day! :)
