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Finding the Fourth Proportional to 642.45, 961.89 and 422.40

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Solution

The fourth proportional to 642.45, 961.89 and 422.40 is: 632.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.45 : 961.89 = 422.40 : x
  2. Step 2: Convert to fraction form
    642.45/961.89 = 422.40/x
  3. Step 3: Cross multiply
    642.45x = 961.89 × 422.40
  4. Step 4: Simplify right side
    642.45x = 406,302.34
  5. Step 5: Solve for x
    x = 406,302.34/642.45
  6. Step 6: Final answer
    x = 632.43

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.