Since ABCD is a parallelogram, the opposite sides will be parallel and equal,

Consider that AC acts as a transversal to the parallel lines AB and CD, so we can write,

So by the ASA criteria, the triangle AED is congruent to the triangle CEB,
Then the corresponding parts of the triangles will be equal,

Hence Proved.
About 3,000 books because 105 * 28 = 2940
and 2940 rounded to the nearest thousand is 3000. Hope this helps.
Answer:
s=7
p=3s
Step-by-step explanation:
The perimeter is the side length times 3
So the equation would be p=3s
Plug in 21 for p
21=3s
That means s=7
56 + 32 = (8 x 7) + (8 x 4) = 8(7 + 4) (Answer C)
Nearest 10: 4750
<span>Nearest 100: 4800 </span>
<span>Nearest 1000: 5000 </span>
<span>Nearest 10000: 0</span>