Answer: 1521
Step-by-step explanation: use the equation pi times radius square. Your radius is always going to be half your diameter so you'll use 22 instead. Then plug that I'm and you should get 1520.53 rounded would be 1521.
The explicit rule for given sequence is:

Further explanation:
We have to determine first of all if the sequence is arithmetic or geometric.
- If the difference of two consecutive terms is same then the sequence is arithmetic sequence
- If the ratio of two consecutive terms is same then the sequence is geometric sequence
Given sequence is:
12,22,32,42

The common difference is 10 which is same for all consecutive terms. So the sequence is an arithmetic sequence.
The general formula for arithmetic sequence is:

Putting the values of a1 and d

The explicit rule for given sequence is:

Keywords: Arithmetic sequence, Common Difference
Learn more about arithmetic sequence at:
#LearnwithBrainly
Answer:
11700 mm²
Step-by-step explanation:
A rectangle is a quadrilateral with two equal, opposite and parallel sides. Each of the angles in a rectangle is 90°.
The horizontal distance of the rectangle = r + r + r + r = 4r
The vertical distance = r + h + r = 2r + h
Where h is the distance between the midpoint of the 2 up circles and the midpoint of the down circle.
Using Pythagoras:
(2r)² = h² + r²
h² + r² = 4r²
h² = 3r²
h = √3r²
h = r√3
Vertical distance = 2r + h = 2r + r√3
Area of rectangle = vertical distance * horizontal distance
Area = 4r * (2r + r√3) = 8r² + 4r²√3 = 4r²(2 + √3)
Substituting:
Area = 4r²(2 + √3) = 4(28²)(2 + √3) = 11703.711 mm²
Area = 11700 mm² to 3 s.f