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Finding the Fourth Proportional to 1,359.72, 2,039.40 and 385.90

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Solution

The fourth proportional to 1,359.72, 2,039.40 and 385.90 is: 578.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,359.72 : 2,039.40 = 385.90 : x
  2. Step 2: Convert to fraction form
    1,359.72/2,039.40 = 385.90/x
  3. Step 3: Cross multiply
    1,359.72x = 2,039.40 × 385.90
  4. Step 4: Simplify right side
    1,359.72x = 786,999.36
  5. Step 5: Solve for x
    x = 786,999.36/1,359.72
  6. Step 6: Final answer
    x = 578.80

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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.