Answer:
1st - Yes ; 2nd - Yes ; 3rd - Yes ; 4th - No
Step-by-step explanation:
Answer:

Step-by-step explanation:
In rectangle ABCD, AB = 6, BC = 8, and DE = DF.
ΔDEF is one-fourth the area of rectangle ABCD.
We want to determine the length of EF.
First, we can find the area of the rectangle. Since the length AB and width BC measures 6 by 8, the area of the rectangle is:

The area of the triangle is 1/4 of this. Therefore:

The area of a triangle is half of its base times its height. The base and height of the triangle is DE and DF. Therefore:

Since DE = DF:

Thus:

Since ABCD is a rectangle, ∠D is a right angle. Then by the Pythagorean Theorem:

Therefore:

Square:

Add:

And finally, we can take the square root of both sides:

It could sometimes be proportional. The reasoning here is that if all the items have different prices it won't be, however if the items you are ordering all have the same price they will be!
Answer:
53lbs.
Step-by-step explanation:
If Kevin bought 3 20lbs. Bags of gravel he would have 60 lbs. of gravel. In the end he has 7 lbs. of gravel left he used 53 pounds.
Equations:
7+x=60 or 60-7=53 lbs.