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Finding the Fourth Proportional to 1,281.56, 1,768.80 and 784.49

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Solution

The fourth proportional to 1,281.56, 1,768.80 and 784.49 is: 1,082.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.56 : 1,768.80 = 784.49 : x
  2. Step 2: Convert to fraction form
    1,281.56/1,768.80 = 784.49/x
  3. Step 3: Cross multiply
    1,281.56x = 1,768.80 × 784.49
  4. Step 4: Simplify right side
    1,281.56x = 1,387,605.91
  5. Step 5: Solve for x
    x = 1,387,605.91/1,281.56
  6. Step 6: Final answer
    x = 1,082.75

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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.