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Finding the Fourth Proportional to 928.78, 1,393.11 and 312.49

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Solution

The fourth proportional to 928.78, 1,393.11 and 312.49 is: 468.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.78 : 1,393.11 = 312.49 : x
  2. Step 2: Convert to fraction form
    928.78/1,393.11 = 312.49/x
  3. Step 3: Cross multiply
    928.78x = 1,393.11 × 312.49
  4. Step 4: Simplify right side
    928.78x = 435,332.94
  5. Step 5: Solve for x
    x = 435,332.94/928.78
  6. Step 6: Final answer
    x = 468.71

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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.