Use what you know about the relationships in 30-60-90 right triangles to solve the following problem. A stained-glass window is in the shape of an equilateral triangle with sides that are 36 inches long. How long is the perpendicular bisector of any side?(1 point) Responses 18 inches 18 inches 36 inches 36 inches 9 inches 9 inches 183–√ inches

1 answer

To find the length of the perpendicular bisector of a side in an equilateral triangle, we can use the properties of a 30-60-90 triangle.

  1. The side of the equilateral triangle is 36 inches.
  2. When you draw the perpendicular bisector of one side, it divides the equilateral triangle into two 30-60-90 triangles.
  3. In a 30-60-90 triangle, the sides are in the ratio of \(1 : \sqrt{3} : 2\).

Let's denote:

  • The length of the side (hypotenuse) of the equilateral triangle as 36 inches.
  • Each half of the base of the triangle is \( \frac{36}{2} = 18 \) inches.

In the 30-60-90 triangle formed:

  • The shortest side (opposite the 30-degree angle) is \(18\) inches (half of the base).
  • The longer leg (which is the length of the perpendicular bisector we need to find) corresponds to the opposite side of the 60-degree angle.

From the property of 30-60-90 triangles, the formula for the longer leg is: \[ \text{Longer leg} = \text{short leg} \times \sqrt{3} = 18 \times \sqrt{3} \]

Thus, the length of the perpendicular bisector is: \[ 18\sqrt{3} \text{ inches} \]

Therefore, the closest response available in your options that corresponds to this length is: \(\text{18}\sqrt{3}\) inches.