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Finding the Fourth Proportional to 486.18, 729.12 and 139.48

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Solution

The fourth proportional to 486.18, 729.12 and 139.48 is: 209.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.18 : 729.12 = 139.48 : x
  2. Step 2: Convert to fraction form
    486.18/729.12 = 139.48/x
  3. Step 3: Cross multiply
    486.18x = 729.12 × 139.48
  4. Step 4: Simplify right side
    486.18x = 101,697.66
  5. Step 5: Solve for x
    x = 101,697.66/486.18
  6. Step 6: Final answer
    x = 209.18

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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.