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Finding the Fourth Proportional to 642.94, 887.29 and 422.21

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Solution

The fourth proportional to 642.94, 887.29 and 422.21 is: 582.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.94 : 887.29 = 422.21 : x
  2. Step 2: Convert to fraction form
    642.94/887.29 = 422.21/x
  3. Step 3: Cross multiply
    642.94x = 887.29 × 422.21
  4. Step 4: Simplify right side
    642.94x = 374,623.87
  5. Step 5: Solve for x
    x = 374,623.87/642.94
  6. Step 6: Final answer
    x = 582.68

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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.