Answer:
Use the formula π*(r^2) where r is radius
Area of big circle, all 3=314.1592654 (approximately) and this is =100%
Area of middle circle=153.93804
Area of small circle=78.53981634
Percentage of middle circle with small circle = (153.93804/314.1592654)*100= 48.999999999999 approx= 49%
Percentage of small circle alone = (78.53981634/314.1592654)*100
= 25%
So 51%= big circle alone
And 51%+25%= 76%
100%-76%=24%
Step-by-step explanation:

The simplest method is "brute force". Calculate each term and add them up.
∑ = 3(1) + 3(2) + 3(3) + 3(4) + 3(5)
∑ = 3 + 6 + 9 + 12 + 15
∑ = 45

∑ = (2×1)² + (2×2)² + (2×3)² + (2×4)²
∑ = 4 + 16 + 36 + 64
∑ = 120

∑ = (2×3−10) + (2×4−10) + (2×5−10) + (2×6−10)
∑ = -4 + -2 + 0 + 2
∑ = -4
4. 1 + 1/4 + 1/16 + 1/64 + 1/256
This is a geometric sequence where the first term is 1 and the common ratio is 1/4. The nth term is:
a = 1 (1/4)ⁿ⁻¹
So the series is:

5. -5 + -1 + 3 + 7 + 11
This is an arithmetic sequence where the first term is -5 and the common difference is 4. The nth term is:
a = -5 + 4(n−1)
a = -5 + 4n − 4
a = 4n − 9
So the series is:

She earned $3 more per hour for gardening than for office work.
Cost of the skateboard = $77.99
Amount that he already has = $20
$77.99 - $20 = $57.99
He still needs <u>$57.99</u>
He earns $6 for every lawn he mows.
$57.99 ÷ 6 = 9.65
He needs to move <u>10 lawns </u>to earn that $57.99.
He can mow 3 lawns a weekend.
10 ÷ 3 = 3 1/3
He needs to work on <u>4 weekends</u> to mow the 10 lawns.
Answer: It will take him 4 weekends to save enough to buy the skateboard.