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Finding the Fourth Proportional to 485.98, 729 and 139.36

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Solution

The fourth proportional to 485.98, 729 and 139.36 is: 209.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.98 : 729 = 139.36 : x
  2. Step 2: Convert to fraction form
    485.98/729 = 139.36/x
  3. Step 3: Cross multiply
    485.98x = 729 × 139.36
  4. Step 4: Simplify right side
    485.98x = 101,593.44
  5. Step 5: Solve for x
    x = 101,593.44/485.98
  6. Step 6: Final answer
    x = 209.05

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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.