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Finding the Fourth Proportional to 1,200.17, 1,800.31 and 420.25

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Solution

The fourth proportional to 1,200.17, 1,800.31 and 420.25 is: 630.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,200.17 : 1,800.31 = 420.25 : x
  2. Step 2: Convert to fraction form
    1,200.17/1,800.31 = 420.25/x
  3. Step 3: Cross multiply
    1,200.17x = 1,800.31 × 420.25
  4. Step 4: Simplify right side
    1,200.17x = 756,580.28
  5. Step 5: Solve for x
    x = 756,580.28/1,200.17
  6. Step 6: Final answer
    x = 630.39

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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.