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Finding the Fourth Proportional to 1,278.66, 1,765.68 and 807.40

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Solution

The fourth proportional to 1,278.66, 1,765.68 and 807.40 is: 1,114.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.66 : 1,765.68 = 807.40 : x
  2. Step 2: Convert to fraction form
    1,278.66/1,765.68 = 807.40/x
  3. Step 3: Cross multiply
    1,278.66x = 1,765.68 × 807.40
  4. Step 4: Simplify right side
    1,278.66x = 1,425,610.03
  5. Step 5: Solve for x
    x = 1,425,610.03/1,278.66
  6. Step 6: Final answer
    x = 1,114.93

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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.