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Finding the Fourth Proportional to 485.48, 728.24 and 138.84

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Solution

The fourth proportional to 485.48, 728.24 and 138.84 is: 208.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.48 : 728.24 = 138.84 : x
  2. Step 2: Convert to fraction form
    485.48/728.24 = 138.84/x
  3. Step 3: Cross multiply
    485.48x = 728.24 × 138.84
  4. Step 4: Simplify right side
    485.48x = 101,108.84
  5. Step 5: Solve for x
    x = 101,108.84/485.48
  6. Step 6: Final answer
    x = 208.27

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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.