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Finding the Fourth Proportional to 642.35, 886.88 and 421.68

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Solution

The fourth proportional to 642.35, 886.88 and 421.68 is: 582.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.35 : 886.88 = 421.68 : x
  2. Step 2: Convert to fraction form
    642.35/886.88 = 421.68/x
  3. Step 3: Cross multiply
    642.35x = 886.88 × 421.68
  4. Step 4: Simplify right side
    642.35x = 373,980.61
  5. Step 5: Solve for x
    x = 373,980.61/642.35
  6. Step 6: Final answer
    x = 582.20

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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.