Answer:
1 is 10
2 is 6
3 is -15
Step-by-step explanation:
16 * 20 + .5 * 20 * 8 = 320 + 80 = 400
It opens up. hope this helps
Answer: trapezoid
Step-by-step explanation: A <u>trapezoid</u> is a quadrilateral
with exactly one pair of parallel sides.
Also, quadrilaterals are two-dimensional shapes.
So it's impossible that's its 3-d.
