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Finding the Fourth Proportional to 642.58, 887.05 and 421.61

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Solution

The fourth proportional to 642.58, 887.05 and 421.61 is: 582.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.58 : 887.05 = 421.61 : x
  2. Step 2: Convert to fraction form
    642.58/887.05 = 421.61/x
  3. Step 3: Cross multiply
    642.58x = 887.05 × 421.61
  4. Step 4: Simplify right side
    642.58x = 373,985.24
  5. Step 5: Solve for x
    x = 373,985.24/642.58
  6. Step 6: Final answer
    x = 582.00

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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.