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Finding the Fourth Proportional to 1,005.59, 1,509.20 and 518.78

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Solution

The fourth proportional to 1,005.59, 1,509.20 and 518.78 is: 778.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.59 : 1,509.20 = 518.78 : x
  2. Step 2: Convert to fraction form
    1,005.59/1,509.20 = 518.78/x
  3. Step 3: Cross multiply
    1,005.59x = 1,509.20 × 518.78
  4. Step 4: Simplify right side
    1,005.59x = 782,942.78
  5. Step 5: Solve for x
    x = 782,942.78/1,005.59
  6. Step 6: Final answer
    x = 778.59

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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.