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Finding the Fourth Proportional to 1,005.94, 1,508.25 and 420.78

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Solution

The fourth proportional to 1,005.94, 1,508.25 and 420.78 is: 630.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.94 : 1,508.25 = 420.78 : x
  2. Step 2: Convert to fraction form
    1,005.94/1,508.25 = 420.78/x
  3. Step 3: Cross multiply
    1,005.94x = 1,508.25 × 420.78
  4. Step 4: Simplify right side
    1,005.94x = 634,648.67
  5. Step 5: Solve for x
    x = 634,648.67/1,005.94
  6. Step 6: Final answer
    x = 630.90

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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.