Home / 1,278.20-1,917.30-1,129.40

Finding the Fourth Proportional to 1,278.20, 1,917.30 and 1,129.40

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Solution

The fourth proportional to 1,278.20, 1,917.30 and 1,129.40 is: 1,694.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.20 : 1,917.30 = 1,129.40 : x
  2. Step 2: Convert to fraction form
    1,278.20/1,917.30 = 1,129.40/x
  3. Step 3: Cross multiply
    1,278.20x = 1,917.30 × 1,129.40
  4. Step 4: Simplify right side
    1,278.20x = 2,165,398.62
  5. Step 5: Solve for x
    x = 2,165,398.62/1,278.20
  6. Step 6: Final answer
    x = 1,694.10

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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.