The circumference of the outer ring is 25.12cm, and the circumference of the inner circle is 18.84cm

The circumference of the outer ring is 25.12cm, and the circumference of the inner circle is 18.84cm

If the radius of the outer circle is 4 / PAI and the radius of the inner circle is 3 / Pai, then the area of the ring = ((4 ^ 2-3 ^ 2) / PAI ^ 2) * Pai = 7 / PAI square centimeter

The perimeter of the bottom surface is 18.84cm, and the height is 12cm

Side area: 18.84 × 12 = 226.08 (square centimeter) two bottom areas: 3.14 × (18.84 ／ 3.14 ／ 2) & # 178; × 2 = 3.14 × 9 × 2 = 56.52 (square centimeter) surface area: 226.08 + 56.52 = 282.6 (square centimeter) volume: 3.14 × (18.84 ／ 3.14 ／ 2) & # 178; × 12 = 3.14 × 9 × 12 = 3391

What is the area of a circle with a circumference of 18.84cm?
2. What is the area of the shadow in the figure (draw the largest circle in a semicircle with a diameter of 4cm)?
3. There is an ancient tree in the park (assuming its trunk is round). The staff want to surround it with a guardrail 1m away from it. Now the perimeter of the root of the ancient tree is 7.536m. Please find out the cross-sectional area of the root of the ancient tree and the perimeter of the guardrail
4. An alarm clock, the length of minute hand is 3cm, the tip of minute hand in an hour passes () cm

2、½×л×2²－л×1²=л
3、2×3.14×r=7.536
∴r=1.2
The cross-sectional area is: 3.14 × 1.2 & sup2; = 4.5216 M & sup2;
Perimeter of guardrail: 2 × 3.14 × (1.2 + 1) = 13.816 M
4、2×3.14×3=18.84

Decomposition factors: (1) 5A & # 178; B & # 178; + 23ab-10; (2) 3A & # 178; B & # 178; - 17abxy + 10x & # 178; Y & # 178;;
3.x²-7xy+12y² 4.x^4+7x²-18 5.5x^5-15x³y-20xy²

The process of factoring is cross multiplication. When you are familiar with it, you don't need to draft it
1 (5ab-2)(ab+5) 2 (3ab-2xy)(ab-5xy) 3 (x-3)(x-4) 4 (x^2-2)(x^2+9) 5(5x^3-20xy)(x^2+y)

Given that m and N are opposite to each other, P and Q are reciprocal to each other, and the absolute value of a is 2, find the value of M + n / 2011 + 2012pq + 1 / 2A & #

M + n / 2011 + 2012pq + 1 / 2A & # 178;, because m and N are reciprocal, so here m + n / 2011 = 0; and PQ is reciprocal, so here 2012pq = 2012 × 1 = 2012:; because the absolute value of a is 2, the prompt given here is the square of a, so no matter whether a is negative or positive, under the square, it is a positive number [negative is positive, positive is positive], then 1 / 2A & # 178; = 1 / 2 × 2 × 2 = 2, So the answer is 2012 + 2 = 2014,

X and y are opposite to each other, m and N are reciprocal to each other, the absolute value of a is equal to 1, find the square of a - (x + y) to the power of 2011+（
X and y are opposite to each other, m and N are reciprocal to each other, the absolute value of a is equal to 1, find the square of a - (x + y) to the power of 2011 + (- Mn) to the power of 2012

x+y-0
mn=1
a²=1
a²-（x+y)^2011+(-mn)^2012
=1-0+(-1)^2012
=1-0+1
=2

Given that the value of m square + 4m + 9 is equal to 5, find the value of 0.25m square + M-10

The square of M + 4m + 9 is equal to 5,
m^2+4m+9=5,
m^2+4m+4+5=5
(m+2)^2=0,
m+2=0
m=-2
So 0.25m ^ 2 + M-10
=0.25(-2)^2+(-2)-10
=0.25*4-2-10
=1-12
=-11

Find all pairs of positive integers (m, n) so that m ^ 2-4n and n ^ 2-4m are complete square numbers

Because m, n is a positive integer, so m ^ 2-4n0) - 4N = - 2mA + A ^ 2, that is, n = a (2m-A) / 4, so n ^ 2-4m = a ^ 2 (2m-A) ^ 2 / 4-4m, because n is a positive integer, so a (2m-A) can be divisible by 4, so a is even. Let a = 2B, (b > 0), then n ^ 2-4m = (b (M-B)) ^ 2-4m = C ^ 2B ^ 2m ^ 2 - (2B ^ 3 + 4) m + B ^ 4-C ^ 2 = 0

Given that (M - 2) ^ 2 + 4 is a complete square number, find the value of integer M

(m-2) ^ 2 + 4 is a perfect square,
m-2=0
m=2

Given the square of (1-m) + |n + 2 | = 0, then the value of (M + n) to the power of 2013 is () A. - 1 B. - 3 C
If the square of (1-m) + | n + 2 | = 0, then the value of (M + n) to the power of 2013 is ()
A.-1
B.-3
C.3
D. Not sure

a