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Finding the Fourth Proportional to 480.81, 721.34 and 138.81

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Solution

The fourth proportional to 480.81, 721.34 and 138.81 is: 208.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    480.81 : 721.34 = 138.81 : x
  2. Step 2: Convert to fraction form
    480.81/721.34 = 138.81/x
  3. Step 3: Cross multiply
    480.81x = 721.34 × 138.81
  4. Step 4: Simplify right side
    480.81x = 100,131.01
  5. Step 5: Solve for x
    x = 100,131.01/480.81
  6. Step 6: Final answer
    x = 208.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.