Answer:
28
Step-by-step explanation:
The attached figure shows 7 triangles (counting the original 2). Each has degree-4 rotational symmetry about the center of the figure, so there can be 7×4 = 28 triangles.
Based on the calculations, all of the numbers belong to this arithmetic sequence.
<h3>How to calculate an arithmetic sequence?</h3>
Mathematically, the nth term of an arithmetic sequence can be calculated by using this expression:

<u>Where:</u>
- d is the common difference.
- a₁ is the first term of an arithmetic sequence.
- n is the total number of terms.
Next, we would determine the common difference as follows:
d = a₂ - a₁
d = 105 - 99 = 6.
d = a₃ - a₂
d = 111 - 105 = 6.
d = a₄ - a₃
d = 117 - 111 = 6.
Based on the calculations, all of the numbers belong to this arithmetic sequence.
Read more on arithmetic sequence here: brainly.com/question/12630565
#SPJ1
Complete Question:
What is the number that does not belong to this sequence 99, 105, 111, 117, 123, 129, 135, 141, 147, 153
9(2k+3)+2=11(k-y)
18k + 27 + 2 = 11k - 11y
18k + 29 = 11k - 11y
18k - 11k + 29 = 11k - 11y - 11k
7k + 29 = -11y
7k + 29 - 29 = -11y - 29
7k = -11y - 29
7k / 7 = -11/7y - 29/7
K = -11/7y - 29/7
Step-by-step explanation:
area of a circle = 19.7cm²
πr²= 19.7cm²
22/7 r²= 19.7
r= 2.50 cm