The perimeter of a triangle with equal sides is 7 cm larger than the perimeter of the rectangle.

The perimeter of a triangle with equal sides is 7 cm larger than the perimeter of the rectangle. What is the side of the triangle if the sides of the rectangle are 4 cm and 6 cm.

Brief entry:
P △ ˃ P rectangular. 7 cm.;
The sides △ are equal;
Length – 6 cm.;
Width – 4 cm.;
Side △ =?
Decision:
1) The perimeter of a rectangle is twice the sum of its length and width:
P is rectangular. = 2 * (6 + 4) = 2 * 10 = 20 (see);
2) Since the perimeter of the triangle is 7 cm larger than the perimeter of the rectangle, it means:
P △ = P rectangle. + 7;
P △ = 20 + 7;
P △ = 27;
3) Since in a given triangle all sides are equal, then the side of the triangle is equal to the quotient of dividing the perimeter of the triangle by three:
27: 3 = 9 (see)
Answer: 9 cm.