The area formula of a circle is 
× π.
With that being said, we can solve both problems!
Starting with part A:
-The radius we know is 21cm. From there, we can substitute in our formula with the new value.
x π
From there, we can square our radius:
(21 x 21) x π
(441) x π
And finally, we can multiply by pi to get our answer.
(441) x π
1385.44236023
Which rounded to the nearest tenth is 1385.4. Therefore, the area of the porthole is 1385.4 centimetres.
The second part can be followed with the same process, hopefully you understand the concept enough to where you're comfortable solving problems like this on your own. Feel free to reach out if you have any further trouble!
<em>Hope this helped! :)</em>
Marco is 10 times greater than salima
Answer:
505
Step-by-step explanation:
sn=2a+(n-1)d
2*5+(100-1)5
10+(99)5
505
18 is the least common denominator of all the fractions, so you can eliminate fractions by multiplying the equation by 18.
(4.5*18)x +((7/9)*18)x + (2 1/3)*18 + ((1/6)*18)x = (5 1/18)*18
81x +14x +42 +3x = 91 . . . . . simplify
Collect terms.
98x + 42 = 91
98x = 49 . . . . . . . . . subtract 42
x = 49/98 = 1/2
The solution is x = 1/2.
_____
You can also do the arithmetic with mixed numbers and fractions. The usual methods apply.
(4.5 + 7/9 + 1/6)x + 2 1/3 = 5 1/18
(49/9)x + 7/3 = 91/18
(49/9)x = 49/18 . . . . . . . subtract 7/3
x = (9/49)(49/18) = 9/18 = 1/2 . . . . . multiply by 9/49
This can be a little more tedious than the method above, but it works and it will give you the right answer. A calculator that works with fractions can make this solution as easy as the other one.
Answer:
a4 = 189
Step-by-step explanation:
Geometric sequence:
In a geometric sequence, the quotient r between consecutive terms is always the same.
The nth term of the sequence is given by:
In which 
is the first term.
In this question:
The fourth term is:
So
a4 = 189
