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Finding the Fourth Proportional to 642.56, 886.50 and 421.63

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Solution

The fourth proportional to 642.56, 886.50 and 421.63 is: 581.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.56 : 886.50 = 421.63 : x
  2. Step 2: Convert to fraction form
    642.56/886.50 = 421.63/x
  3. Step 3: Cross multiply
    642.56x = 886.50 × 421.63
  4. Step 4: Simplify right side
    642.56x = 373,772.78
  5. Step 5: Solve for x
    x = 373,772.78/642.56
  6. Step 6: Final answer
    x = 581.70

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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.