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Finding the Fourth Proportional to 630.90, 870.17 and 420.98

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Solution

The fourth proportional to 630.90, 870.17 and 420.98 is: 580.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    630.90 : 870.17 = 420.98 : x
  2. Step 2: Convert to fraction form
    630.90/870.17 = 420.98/x
  3. Step 3: Cross multiply
    630.90x = 870.17 × 420.98
  4. Step 4: Simplify right side
    630.90x = 366,320.87
  5. Step 5: Solve for x
    x = 366,320.87/630.90
  6. Step 6: Final answer
    x = 580.63

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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.