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Finding the Fourth Proportional to 430.88, 642.70 and 392

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Solution

The fourth proportional to 430.88, 642.70 and 392 is: 584.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.88 : 642.70 = 392 : x
  2. Step 2: Convert to fraction form
    430.88/642.70 = 392/x
  3. Step 3: Cross multiply
    430.88x = 642.70 × 392
  4. Step 4: Simplify right side
    430.88x = 251,938.40
  5. Step 5: Solve for x
    x = 251,938.40/430.88
  6. Step 6: Final answer
    x = 584.71

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.