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Finding the Fourth Proportional to 684.60, 1,026.08 and 319.40

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Solution

The fourth proportional to 684.60, 1,026.08 and 319.40 is: 478.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.60 : 1,026.08 = 319.40 : x
  2. Step 2: Convert to fraction form
    684.60/1,026.08 = 319.40/x
  3. Step 3: Cross multiply
    684.60x = 1,026.08 × 319.40
  4. Step 4: Simplify right side
    684.60x = 327,729.95
  5. Step 5: Solve for x
    x = 327,729.95/684.60
  6. Step 6: Final answer
    x = 478.72

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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.