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Finding the Fourth Proportional to 928.38, 1,392.78 and 279.12

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Solution

The fourth proportional to 928.38, 1,392.78 and 279.12 is: 418.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.38 : 1,392.78 = 279.12 : x
  2. Step 2: Convert to fraction form
    928.38/1,392.78 = 279.12/x
  3. Step 3: Cross multiply
    928.38x = 1,392.78 × 279.12
  4. Step 4: Simplify right side
    928.38x = 388,752.75
  5. Step 5: Solve for x
    x = 388,752.75/928.38
  6. Step 6: Final answer
    x = 418.74

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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.