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Finding the Fourth Proportional to 878.78, 1,316.55 and 781.58

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Solution

The fourth proportional to 878.78, 1,316.55 and 781.58 is: 1,170.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.78 : 1,316.55 = 781.58 : x
  2. Step 2: Convert to fraction form
    878.78/1,316.55 = 781.58/x
  3. Step 3: Cross multiply
    878.78x = 1,316.55 × 781.58
  4. Step 4: Simplify right side
    878.78x = 1,028,989.15
  5. Step 5: Solve for x
    x = 1,028,989.15/878.78
  6. Step 6: Final answer
    x = 1,170.93

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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.