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Finding the Fourth Proportional to 630.80, 869.66 and 421

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Solution

The fourth proportional to 630.80, 869.66 and 421 is: 580.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    630.80 : 869.66 = 421 : x
  2. Step 2: Convert to fraction form
    630.80/869.66 = 421/x
  3. Step 3: Cross multiply
    630.80x = 869.66 × 421
  4. Step 4: Simplify right side
    630.80x = 366,126.86
  5. Step 5: Solve for x
    x = 366,126.86/630.80
  6. Step 6: Final answer
    x = 580.42

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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.