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Finding the Fourth Proportional to 480.75, 721.13 and 138.75

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Solution

The fourth proportional to 480.75, 721.13 and 138.75 is: 208.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    480.75 : 721.13 = 138.75 : x
  2. Step 2: Convert to fraction form
    480.75/721.13 = 138.75/x
  3. Step 3: Cross multiply
    480.75x = 721.13 × 138.75
  4. Step 4: Simplify right side
    480.75x = 100,056.09
  5. Step 5: Solve for x
    x = 100,056.09/480.75
  6. Step 6: Final answer
    x = 208.13

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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.