where r is the radius of a circle.
Answer:
You need to find the radius first,
Half of 23 is = 11.5
Formula you must remember when finding area of circle is:
πr^2
(pie (3.14 or 22/7) x radius squared)
Our pie is 3.14 because they said to use it in this particular question.
3.14 x 11.5^2 (remember we are making our radius squared) <--- Before
Let's evaluate first:
3.14 x 132.25 <--- After evaluating
So, 3.14 x 132.25 = 415.265 <----- your answer
_______
2x(3y+2) is the answer. First find the LCM of 6 and 4 which is 2 and look out for the common variables on both sides which is x and follow the due process
Answer:
81.25 mL
Why?
Total amount of millilitres: 125 mL
Let x represent the millilitres of acid.
Let a represent the amount of acid in the 50 mL solution.
Let b represent the amount of acid in the 75 mL solution.
This means that x = 125 - (a + b)
So, a = 0.2*50
a = 10
So, b = 0.45*75
b = 33.75
Plug it into our equation;
x = 125 - (a + b)
x = 125 - (10 + 33.75)
x = 125 - 43.75
x = 81.25
Therefore, 81.25 mL of the 125 mL mixture is acid.
Alternate solution:
Let x represent the millilitres of acid.
Let a represent the number of millilitres in the mixture.
Let b represent the percentage of acid in the mixture.
This means that x = b*a
So, a = 50 + 75
a = 125
So, b = 0.2 + 0.45
b = 0.65
Plug it into our equation;
x = b*a
x = 0.65*125
x = 81.25
Therefore, 81.25 mL of the 125 mL mixture is acid.
(Hope this helps)
