20 and that should be correct, if you need an explanation just ask
Answer:
Circumference = πd
where d = diameter
Step-by-step explanation:
When using this formula you don't need to multiply by 2 like you do when using the radius because the diameter is twice the radius of a circle.
Answer:
A and C
Step-by-step explanation:
solving the equations
A
x² - 4 = 0 ( add 4 to both sides )
x² = 4 ( take square root of both sides )
x = ± 
= ± 2 ← required solution
B
x² = - 4 ← has no real solutions
C
4x² = 16 ( divide both sides by 4 )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
D
2(x - 2)² = 0 , then
x- 2 = 0 ( add 2 to both sides )
x = 2 ← not the required solution
Look at it this way:
When you flip a coin, the probability of it landing with EITHER side showing
is 100%.
This leads us to the rule ...
The sum of the probabilities of
all possible outcomes is 100%.
For a coin: (probability of heads) plus (probability of tails) = 100%.
That just says: We're 100% sure that the coin will land with either
heads or tails up.
An "honest" coin gets heads 50% of the time and tails the other 50%.
But if the coin is all bent and squashed and has a feather stuck to
one side and a wad of gum on the other side so that it comes up
heads 70% of the time, then the coin isn't 'honest'. But it still has to
land EITHER heads OR tails, so the sum of the probabilities is still 100%.
So the probability of heads is 30%.
