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Finding the Fourth Proportional to 928.12, 1,392.57 and 407.85

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Solution

The fourth proportional to 928.12, 1,392.57 and 407.85 is: 611.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.12 : 1,392.57 = 407.85 : x
  2. Step 2: Convert to fraction form
    928.12/1,392.57 = 407.85/x
  3. Step 3: Cross multiply
    928.12x = 1,392.57 × 407.85
  4. Step 4: Simplify right side
    928.12x = 567,959.67
  5. Step 5: Solve for x
    x = 567,959.67/928.12
  6. Step 6: Final answer
    x = 611.95

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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.