Open Middle®
Directions: Using the integers -9 to 9 at most one time each, fill in the boxes to create coordinates that represent the vertices of two triangles: one with an area of less than 55 units2 and one with an area of more than 55 units2. You may reuse all the integers each time.
Hint
How can you graphically estimate your triangle’s area before you calculate it?
Answer
There are many possible answers. One is:
Greater than 55 units2 which has an area 121.5 units2
(-9, -8), (0, 8), and (9, -3)
Greater than 55 units2 which has an area 121.5 units2
(-9, -8), (0, 8), and (9, -3)
Less than 55 units2
(-3, 1), (0, 4), and (3, -4) which has an area 16.5 units2
Source: Robert Kaplinsky
