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Finding the Fourth Proportional to 684.12, 1,026.60 and 318.72

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Solution

The fourth proportional to 684.12, 1,026.60 and 318.72 is: 478.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.12 : 1,026.60 = 318.72 : x
  2. Step 2: Convert to fraction form
    684.12/1,026.60 = 318.72/x
  3. Step 3: Cross multiply
    684.12x = 1,026.60 × 318.72
  4. Step 4: Simplify right side
    684.12x = 327,197.95
  5. Step 5: Solve for x
    x = 327,197.95/684.12
  6. Step 6: Final answer
    x = 478.28

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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.