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Finding the Fourth Proportional to 1,125.78, 1,688.64 and 509.31

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Solution

The fourth proportional to 1,125.78, 1,688.64 and 509.31 is: 763.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,125.78 : 1,688.64 = 509.31 : x
  2. Step 2: Convert to fraction form
    1,125.78/1,688.64 = 509.31/x
  3. Step 3: Cross multiply
    1,125.78x = 1,688.64 × 509.31
  4. Step 4: Simplify right side
    1,125.78x = 860,039.33
  5. Step 5: Solve for x
    x = 860,039.33/1,125.78
  6. Step 6: Final answer
    x = 763.95

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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.