Home / 1,398.20-1,929.56-768.78

Finding the Fourth Proportional to 1,398.20, 1,929.56 and 768.78

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Solution

The fourth proportional to 1,398.20, 1,929.56 and 768.78 is: 1,060.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.20 : 1,929.56 = 768.78 : x
  2. Step 2: Convert to fraction form
    1,398.20/1,929.56 = 768.78/x
  3. Step 3: Cross multiply
    1,398.20x = 1,929.56 × 768.78
  4. Step 4: Simplify right side
    1,398.20x = 1,483,403.29
  5. Step 5: Solve for x
    x = 1,483,403.29/1,398.20
  6. Step 6: Final answer
    x = 1,060.94

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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.