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Finding the Fourth Proportional to 486.20, 729.35 and 139.53

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Solution

The fourth proportional to 486.20, 729.35 and 139.53 is: 209.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.20 : 729.35 = 139.53 : x
  2. Step 2: Convert to fraction form
    486.20/729.35 = 139.53/x
  3. Step 3: Cross multiply
    486.20x = 729.35 × 139.53
  4. Step 4: Simplify right side
    486.20x = 101,765.51
  5. Step 5: Solve for x
    x = 101,765.51/486.20
  6. Step 6: Final answer
    x = 209.31

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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.