Answer: 
Step-by-step explanation:
You know that the triangle ABC and the triangle DEF are similar.
Therefore, if the lenght of AC is 12 centimeters and the lenght of DF is 10 centimeters, then you can find the ratio as following:

Then, the calculte the length of EF, you must multiply the lenght BC of the triangle ABC by the ratio obtained above.
Therefore, the lenght EF is the following:

0.0119047619 is the answer
Answer:
L=3w+2...L+w=40... 4w+2=40...w=3/5 and L=30/5
You need to make a draw of the problem to understand what to do.
The height of the pyramid, and half the original base side length make a rectangle triangle, whose hypothenuse is the height of the lateral area of one of the pyramids faces, so we have. So we use Pythagoras:
hyp^2 = 11^2 + 14^2 = 317
hyp = 17.8 m
that is the height of the lateral area triangle
Now to find the area of the lateral area triangle, we have:
a = base*height/2 = 22*17.8/2
a = 195.8 m^2
that is the lateral area of the pyramid, 196 m^2
Volume=length×width×<span>height
= 1 X 1 X 1 = 1
YOUR ANSWE IS C THE ANSWER IS 1 CUBIC UNIT
</span>