Question

Find the perimeter of a train of 100 equilateral triangles if the triangles are joined side to side. Each side is one inch long. Write an equation to determine the perimeter of the triangle train.

Answer 1

To calculate the perimeter of 100 equilateral triangles joined side to side, each with a side of one inch, use the formula P = 2s + (n - 1)s. With s = 1 inch and n = 100, the perimeter is 101 inches.

Step-by-step explanation:

To find the perimeter of a train of 100 equilateral triangles, we start by acknowledging that each triangle contributes two sides to the perimeter since they are joined side to side. An individual equilateral triangle has three sides of equal length; however, when joined in a train, the shared side does not contribute to the perimeter. Therefore, the equation to determine the perimeter (P) of the triangle train with 100 triangles, each with a side length (s) of one inch, would be:

P = 2s + (n - 1)s

Where n is the number of triangles in the train. Plugging in the values, we get:

P = 2(1 inch) + (100 - 1)(1 inch) = 2 inches + 99 inches = 101 inches.

This calculation shows that the perimeter of a train of 100 equilateral triangles, each with sides of one inch, is 101 inches.

Answer 2

102

Step-by-step explanation:

Each triangle will have a perimeter of 3. When joined, the outside triangles will have 2 sides showing, or 2 inches. The middle 98 will only have one free side, or one inch. This means that 98*1 + 2*2 = 102