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Finding the Fourth Proportional to 728.80, 1,005.74 and 397.22

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Solution

The fourth proportional to 728.80, 1,005.74 and 397.22 is: 548.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.80 : 1,005.74 = 397.22 : x
  2. Step 2: Convert to fraction form
    728.80/1,005.74 = 397.22/x
  3. Step 3: Cross multiply
    728.80x = 1,005.74 × 397.22
  4. Step 4: Simplify right side
    728.80x = 399,500.04
  5. Step 5: Solve for x
    x = 399,500.04/728.80
  6. Step 6: Final answer
    x = 548.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.