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Finding the Fourth Proportional to 630.40, 870 and 397.60

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Solution

The fourth proportional to 630.40, 870 and 397.60 is: 548.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    630.40 : 870 = 397.60 : x
  2. Step 2: Convert to fraction form
    630.40/870 = 397.60/x
  3. Step 3: Cross multiply
    630.40x = 870 × 397.60
  4. Step 4: Simplify right side
    630.40x = 345,912
  5. Step 5: Solve for x
    x = 345,912/630.40
  6. Step 6: Final answer
    x = 548.72

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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.