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Finding the Fourth Proportional to 1,281.85, 1,769.11 and 784.56

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Solution

The fourth proportional to 1,281.85, 1,769.11 and 784.56 is: 1,082.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.85 : 1,769.11 = 784.56 : x
  2. Step 2: Convert to fraction form
    1,281.85/1,769.11 = 784.56/x
  3. Step 3: Cross multiply
    1,281.85x = 1,769.11 × 784.56
  4. Step 4: Simplify right side
    1,281.85x = 1,387,960.17
  5. Step 5: Solve for x
    x = 1,387,960.17/1,281.85
  6. Step 6: Final answer
    x = 1,082.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.