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Finding the Fourth Proportional to 765.78, 1,054.80 and 678.30

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Solution

The fourth proportional to 765.78, 1,054.80 and 678.30 is: 934.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.78 : 1,054.80 = 678.30 : x
  2. Step 2: Convert to fraction form
    765.78/1,054.80 = 678.30/x
  3. Step 3: Cross multiply
    765.78x = 1,054.80 × 678.30
  4. Step 4: Simplify right side
    765.78x = 715,470.84
  5. Step 5: Solve for x
    x = 715,470.84/765.78
  6. Step 6: Final answer
    x = 934.30

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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.