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Finding the Fourth Proportional to 642.32, 886 and 393.40

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Solution

The fourth proportional to 642.32, 886 and 393.40 is: 542.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.32 : 886 = 393.40 : x
  2. Step 2: Convert to fraction form
    642.32/886 = 393.40/x
  3. Step 3: Cross multiply
    642.32x = 886 × 393.40
  4. Step 4: Simplify right side
    642.32x = 348,552.40
  5. Step 5: Solve for x
    x = 348,552.40/642.32
  6. Step 6: Final answer
    x = 542.65

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.