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Finding the Fourth Proportional to 485.05, 728.38 and 318.55

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Solution

The fourth proportional to 485.05, 728.38 and 318.55 is: 478.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.05 : 728.38 = 318.55 : x
  2. Step 2: Convert to fraction form
    485.05/728.38 = 318.55/x
  3. Step 3: Cross multiply
    485.05x = 728.38 × 318.55
  4. Step 4: Simplify right side
    485.05x = 232,021.81
  5. Step 5: Solve for x
    x = 232,021.81/485.05
  6. Step 6: Final answer
    x = 478.35

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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.