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Finding the Fourth Proportional to 485.66, 728.36 and 138.99

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Solution

The fourth proportional to 485.66, 728.36 and 138.99 is: 208.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.66 : 728.36 = 138.99 : x
  2. Step 2: Convert to fraction form
    485.66/728.36 = 138.99/x
  3. Step 3: Cross multiply
    485.66x = 728.36 × 138.99
  4. Step 4: Simplify right side
    485.66x = 101,235.66
  5. Step 5: Solve for x
    x = 101,235.66/485.66
  6. Step 6: Final answer
    x = 208.45

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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.