Let O be the point of intersection of diagonals.
Consider triangles FOE and EOD:
FO = OD, ∠FOE = ∠EOD and OE is a common side ⇒
triangles FOE and EOD are congruent.
In congruent triangles all corresponding sides and are congruent ⇒
EF = DE = 6
The decimal you put would be “two ten-millionths” if read out loud. If the allowable amount is 10 parts per billion, it would be 1 part per 100 million. Because 2 parts per 10 million is also 20 parts per 100 million, it is not not an acceptable amount
Answer:
Factoring the expression
completely we get 
Step-by-step explanation:
We need to factor the expression
completely
We need to find common terms in the expression.
Looking at the expression, we get
is common in both terms, so we can write:

So, taking out the common expression we get: 
Now, we can factor the term (1+x^3) or we can write (x^3+1) by using formula:

So, we get:

Therefor factoring the expression
completely we get 
Answer:
<h3> 26²/₃ liters of 15% acid and 13¹/₃ liters of 33% acid</h3>
Step-by-step explanation:
Concentration Amount of Amount
of Solution Solution (L) of Acid
15% x 0.15x
33% y 0.33y
21% 40 0.21•40
x + y = 40 ⇒ x = 40 - y
0.15x + 0.33y = 0.21•40
0.15(40 - y) + 0.33y = 0.21•40
6 - 0.15y + 0.33y = 8.4
0.18y = 2.4
y = 13¹/₃
x = 40 - 13¹/₃ = 26²/₃