i need help i don't understand ! HELP NEEDED

Question

TO FIND THE AREA I MULTIPLY ALL MY SIDES

3X6.7X6

WHAT AM I DOING WRONG

Answer 1

The mistake is that you are multiplying all three sides of the triangle. Remember the formula to find the area of a triangle is:

Area = 1/2 x base x height

The base and height must form a right angle, which means they must be perpendicular (cross at 90°) to each other. In the triangle shown, the top side labeled 3 and the left side labeled 6 form a right angle, so those are the base and the height.

So, we just plug them into the formula:

Area = 1/2 x 3 x 6

= 1/2 x 18

= 9

So, the area is 9 units², which is option D.

Answer 2

So actually because it's a right triangle, multiplying all sides won't give you the area. Instead, because it's a right triangle, you actually would multiply sides a and b (3 and 6) which will give you 18, which would be the area of a square with two sides that are 3 and two sides that are 6. But this is a right triangle, which is actually half of a square when you cut it in half diagonally. So if you divide 18 (area of a square with 3 and 6) than you get the area of the right triangle, which is 9.

Math

A = (a*b)/2

A = 3*6/2

A = 18/2 = 9

Hope this helps!