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Finding the Fourth Proportional to 485.71, 728.61 and 139.04

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Solution

The fourth proportional to 485.71, 728.61 and 139.04 is: 208.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.71 : 728.61 = 139.04 : x
  2. Step 2: Convert to fraction form
    485.71/728.61 = 139.04/x
  3. Step 3: Cross multiply
    485.71x = 728.61 × 139.04
  4. Step 4: Simplify right side
    485.71x = 101,305.93
  5. Step 5: Solve for x
    x = 101,305.93/485.71
  6. Step 6: Final answer
    x = 208.58

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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.