The circumference of isosceles triangle is 30cm, one side is 12cm, and the other side is 12cm______ ．

The circumference of isosceles triangle is 30cm, one side is 12cm, and the other side is 12cm______ ．

(1) When 12 is the waist length, the bottom edge is 30-12 × 2 = 6, then 6, 12 and 12 can form a triangle, so the length of the other two sides is 12,6; (2) when 12 is the bottom edge length, the waist length is 12 × (30-12) = 9, then 9, 9 and 12 can form a triangle, so the length of the other two sides is 9,9

The perimeter of a square is 5 / 1 less than that of a circle. It is known that the side length of a square is 2.512 meters. How many square meters is the area of this circle

The perimeter of a square is one fifth less than that of a circle, that is to say, the perimeter of a square is four fifths of that of a circle. The perimeter of a square is the sum of four sides, which is equal to 2.512x4 = 10.048 (m), then the perimeter of a circle is equal to 10.048 △ 0.8 = 12.56 (m), and the radius of a circle is equal to 12.56 △ 2 π = 12.56 △ 2x3

The perimeter of a square and a circle is equal. The perimeter of a square is 6.28 meters. What is the area of a circle?

The radius of the circle is 6.28 ÷ (2 * 3.14) = 1m
The area of the circle is 3.14 * 1 * 1 = 3.14 square meters