Math Problem Statement

In circle V, m∠WVX = 20° and the length of WX = (2/3)π. Find the length of VW.

Solution

In this problem, you are given a circle VV, where WW and XX are points on the circle, and you're asked to find the length of the segment VW\overline{VW}.

Here's what we know:

  • The measure of WVX=20\angle WVX = 20^\circ.
  • The length of arc WX=23πWX = \frac{2}{3}\pi.

The key point here is that the angle given, WVX\angle WVX, is the central angle subtended by the arc WXWX. This means that the arc length WXWX can be related to the circle's radius rr, which is the length of VWVW, since VWVW is a radius of the circle.

Step 1: Use the formula for arc length

The formula for the length of an arc is: Arc length=r×θ\text{Arc length} = r \times \theta where:

  • rr is the radius (which is VWVW),
  • θ\theta is the central angle in radians.

We are given that the length of arc WX=23πWX = \frac{2}{3}\pi, and we know that the central angle θ=20\theta = 20^\circ. To use this formula, we need to convert the angle into radians.

θ=20×π180=π9radians\theta = 20^\circ \times \frac{\pi}{180^\circ} = \frac{\pi}{9} \, \text{radians}

Step 2: Set up the equation

Using the arc length formula: 23π=r×π9\frac{2}{3}\pi = r \times \frac{\pi}{9}

Step 3: Solve for rr (which is VWVW)

Now, solve for rr: r=23ππ9=23×91=6r = \frac{\frac{2}{3}\pi}{\frac{\pi}{9}} = \frac{2}{3} \times \frac{9}{1} = 6

Thus, the length of VW=6\overline{VW} = 6.

Would you like any further details or clarification on the steps?


Here are five additional questions related to this topic:

  1. How would the solution change if the angle WVX\angle WVX were 30 degrees instead of 20 degrees?
  2. What would be the arc length if the radius VWVW were doubled?
  3. How do you convert degrees to radians in general, and why is it necessary in circle problems?
  4. What is the relationship between the radius of a circle and its circumference?
  5. How can you calculate the area of the sector formed by angle WVX\angle WVX?

Tip: Always make sure to convert angles into radians when working with arc lengths and sectors, as formulas typically use radian measure.

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Math Problem Analysis

Mathematical Concepts

Circle Geometry
Arc Length
Central Angle
Radians Conversion

Formulas

Arc length = r × θ
Angle in radians = (degrees × π) / 180

Theorems

Theorem of Central Angle
Arc Length Theorem

Suitable Grade Level

Grades 9-12