Answer:
The property the equation illustrates would be the zero property of addition.
Step-by-step explanation:
The additive property of zero states that when you have any number and add zero to it, your answer will always equal the original number.
Step-by-step explanation:
Selling price = Rs.80
Cost price = Rs.100
here, CP > SP
Now...
Loss ( L ) = CP - SP
= RS.100 - 80
= Rs.20
Now...
= 20 %
Answer:
1. always
2. sometimes
Step-by-step explanation:
Two lines are coplanar if they lie in the same plane or in parallel planes. There is ALWAYS a plane which contains two parallel lines (see first attached image for details).
Two lines that lie in parallel planes are sometimes parallel. For example, see at second image. Planes 
and 
are parallel. Consider pair of lines 
and 
- they are parallel, but if you consider the pair of lines and 
, you can see they are not parallel.
Let h represent the height of the trapezoid, the perpendicular distance between AB and DC. Then the area of the trapezoid is
Area = (1/2)(AB + DC)·h
We are given a relationship between AB and DC, so we can write
Area = (1/2)(AB + AB/4)·h = (5/8)AB·h
The given dimensions let us determine the area of ∆BCE to be
Area ∆BCE = (1/2)(5 cm)(12 cm) = 30 cm²
The total area of the trapezoid is also the sum of the areas ...
Area = Area ∆BCE + Area ∆ABE + Area ∆DCE
Since AE = 1/3(AD), the perpendicular distance from E to AB will be h/3. The areas of the two smaller triangles can be computed as
Area ∆ABE = (1/2)(AB)·h/3 = (1/6)AB·h
Area ∆DCE = (1/2)(DC)·(2/3)h = (1/2)(AB/4)·(2/3)h = (1/12)AB·h
Putting all of the above into the equation for the total area of the trapezoid, we have
Area = (5/8)AB·h = 30 cm² + (1/6)AB·h + (1/12)AB·h
(5/8 -1/6 -1/12)AB·h = 30 cm²
AB·h = (30 cm²)/(3/8) = 80 cm²
Then the area of the trapezoid is
Area = (5/8)AB·h = (5/8)·80 cm² = 50 cm²
