Given that the three sides of a triangle are (2x + 1) cm, (X & # 178; + 2) cm, (X & # 178; + 2x + 1) cm, then the perimeter of the triangle is (2x + 1) cm

Given that the three sides of a triangle are (2x + 1) cm, (X & # 178; + 2) cm, (X & # 178; + 2x + 1) cm, then the perimeter of the triangle is (2x + 1) cm

The perimeter of this triangle = (2x + 1) + (X & # 178; + 2) + (X & # 178; + 2x + 1)
=2x+1+x²+2+x²+2x+1
=2x²+4x+4 cm

If the circumference of an isosceles triangle is 13cm and the length of its bottom is 1cm longer than the length of its waist, then the length of its bottom is --- cm

Let the waist length be X,
Then the bottom length is x + 1
X + X + X + 1 = 13, x = 4cm

Change a section of iron wire into an equilateral triangle and a square. The side length of the triangle is (1 / 3 × A & # 178; + 1 / 3 × B & # 178; + 3) cm
(2 / 3 × a + B-1) cm to find the length of the wire;

Length is 3 (A & # 178; 3 / 3 + B & # 178 / 3 + 3) = 4 (3a / 2 + B-1)
(a²-6a+9)+(b²-4b+4)=0
(a-3)²+(b-2)²=0
a-3=b-2=0
a=3,b=2
So 4 (3a / 2 + B-1) = 6A + 4b-4 = 22cm
The original formula = (4a & # 178; + 1 + 4a) (4a & # 178; + 1-4a)
=(2a+1)²(2a-1)²

Now we need to use a piece of iron wire to make a square or circle with an area of 18cm and 178 cm. Which figure is short

Square side length = √ 18 = 3 √ 2cm
Wire length = 3 √ 2 × 4 = 12 √ 2cm
Circle radius = √ 18 △ π = √ 6cm
Wire length = 2 π×√ 6 = 6 √ 6cm
Because: 12 √ 2 ＞ 6 √ 6
So: make round wire short