What is the area of the triangle in the figure

The first leg is 4, the second leg is 6. Area= 4*6/2 = 24/2= 12
Your answer is 12mm^2

Logic geometry. Ah, textbooks.

Flip dat triangle!

Turn in onto its base. 

My Geometry teacher used to say, "My students, ahh. Textbooks. They say, 'My pretty little students, here's a formula! I will give you numbers and you plug it in.' Then he would say, 'I don't like textbooks. I'm a rebel! So, I derive the formula.'" He made us derive it. But the formula is this: 1/2 x b x h. Why? The real formula is because two equal triangles are both HALF of a parallelogram, and a parallelogram has formula b x h. So it's 1/2 x b x h.

With that in mind, let's find the height first. Onwards!!

12 mm. What can we do with it? Oh, we know the rectangle has 8 mm!! 12 mm - 8 mm is 4 mm! The height is 4 mm. Onwards to the base!!

Hey, what do we know? The rectangle has length 10 mm. A part of it is 4 mm

Plug in the formula!!

1/2 x 4 x 6 is

12.

And don't forget the mm!!