A 12.56 decimeter long wire encircles a circle. How many square decimeters is the area of this circle

A 12.56 decimeter long wire encircles a circle. How many square decimeters is the area of this circle

12.56/3.14＝4.4/2＝2.2*2*3.14＝12.56

Bend a 9.42 decimeter long wire into the largest circle with a radius of______ The area is______ ．

The radius of this circle is 1.5 decimeters; the area is 7.065 square decimeters. So the answer is: 1.5 decimeters, 7.065 square decimeters

If real numbers a and B satisfy a & # 178; + 5a-1 = 0, B & # 178; + 5b-1 = 0, and ab ≠ 0, then x & # 178; + 5x + 8 =?

Because real numbers a and B satisfy a & # 178; + 5a-1 = 0, B & # 178; + 5b-1 = 0
So a and B are two parts of x ^ 2 + 5x-1 = 0
X^2+5X+8=X^2+5X-1+9=9

55 * 55 simple calculation, to process

Whose square is 9999

Let n be a very small number relative to 100, then: (100-N) &# 178; = 9999, 100 & # 178; - 2 * 100 * n + n & # 178; = 9999
Omit the number n & # 178; which is much smaller than N, that is, 100 & # 178; - 2 * 100 * n = ~ 9999, and 200 * n = ~ 1
N = ~ 1 / 200 = 0.005 last √ 9999 = 100-N = ~ 100-0.005 = 99.995 - answer

Factorization of polynomial 1-A + b-ab
Factorization 1-A + b-ab

1-a+b-ab
=(1-a)-b(1-a)
=(1-a)(1-b)
Glad to answer for you!
Please click the [select as satisfactory answer] button below,

A simple method is used to calculate the equations x + Y-1 = 0.4 (x + y) - 1 / 6 y = 5

x+y-1=0 .1
4(x+y)-y/6=5.2
From Formula 1
x+y=1.3
Substitute formula 3 into formula 2
4*1-y/6=5
y/6=4-5
y/6=-1
y=-6
x+(-6)=1
x=1+6
x=7

(calculation equations x + y) / 2 = 6 - (X-Y) / 3,6 (x + y) - 5 (X-Y) = 18

Simplification
x+11y=18(1)
5x+y=36 (2)
(1)*5-(2)
y=1
(2)*11-(1)
x=7

Calculation by formula: 1998 & # 178; - 1997 * 1999

Gu Ge 22 for you
1998^2-1997x1999
=1998^2-(1998-1)x(1998＋1)
=1998^2-1998^2＋1
=0＋1
=1

-4 + a-178; and - 4-a-178;
Can it be calculated? What's the difference between the two?

The first is: - 4 + A & # 178; = A & # 178; - 4 = (a + 2) (A-2)
The second one can't be: - 4-A & # 178; = - (A & # 178; + 4)
The difference of squares can be calculated, but the sum of squares can't
Hope to adopt