What is the area of the triangle?

21

Step-by-step explanation:

Add 5.3 + 1.7 and you get 7 (7 is the base of the triangle). Multiply 7 by the height (6) and you get 42. When you put 2 triangles together, it will create a quadrilateral. "Cut the quadrilateral in half" and you will get your triangle's area. The area is 21 :)

53.9 square units was my answer, but I learned that it was 21 !

the answer is b.

step-by-step explanation:

identity property is where 0+whatever number=whatever number. basically 0+ a number.