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Finding the Fourth Proportional to 1,261, 1,891.50 and 439.12

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Solution

The fourth proportional to 1,261, 1,891.50 and 439.12 is: 658.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,261 : 1,891.50 = 439.12 : x
  2. Step 2: Convert to fraction form
    1,261/1,891.50 = 439.12/x
  3. Step 3: Cross multiply
    1,261x = 1,891.50 × 439.12
  4. Step 4: Simplify right side
    1,261x = 830,595.48
  5. Step 5: Solve for x
    x = 830,595.48/1,261
  6. Step 6: Final answer
    x = 658.68

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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.