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Finding the Fourth Proportional to 1,200.30, 1,800.72 and 420.30

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Solution

The fourth proportional to 1,200.30, 1,800.72 and 420.30 is: 630.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,200.30 : 1,800.72 = 420.30 : x
  2. Step 2: Convert to fraction form
    1,200.30/1,800.72 = 420.30/x
  3. Step 3: Cross multiply
    1,200.30x = 1,800.72 × 420.30
  4. Step 4: Simplify right side
    1,200.30x = 756,842.62
  5. Step 5: Solve for x
    x = 756,842.62/1,200.30
  6. Step 6: Final answer
    x = 630.54

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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.