Answer:
The radius of the circle is half its diameter. It's the length from the center point straight out to the edge.
1. 137.5%
2. 66.7%
3.48%
4.51.87
Answer:
A) The first 4 terms of the sequences are:
,
,
and
.
B) An explicit formula for this sequence can be written as: 
C) A recursive formula for this sequence can be written as:

Step-by-step explanation:
A) You can find the firs terms of this sequence simply selecting an odd integer and summing the consecutive 3 ones:
(a.1)




B) Observe the sequence of odd numbers 1, 3, 5, 7, 9, 11, 13(...).
You can express this sequence as:
(b.1)
If you merge the expression b.1 in a.1, you obtain the explicit formula of the sequence:
(a.1)
(b.2)
(b.3)
(b.s)
C) The recursive formula has to be written considering an initial term and an N term linked with the previous term. You can see an addition of 8 between a term and the next one. So you can express each term as an addition of 8 with the previous one. Therefore, if the first term is 16:
(c.s)
If Sin 60 = √3 / 2
Then, Cos 60 = ?
Well, we know :
Sin^2x + Cos^2x = 1
Let X = 60°
That is,
Sin^2(60) + Cos^2(60) = 1
(√3 / 2)^2 + Cos^2(60) = 1
3 / 4 + Cos^2(60) = 1
Cos^2(60) = 1 - 3/4
Cos^2(60) = 4/4 - 3/4
Cos^2(60) = (4-3)/4
Cos^2(60) = 1/4
Cos(60) = √(1/4)
Cos(60) = √1 / √4
Cos(60) = 1 / 2
This's answer right to the your question.