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Finding the Fourth Proportional to 847.78, 1,170.78 and 645.54

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Solution

The fourth proportional to 847.78, 1,170.78 and 645.54 is: 891.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    847.78 : 1,170.78 = 645.54 : x
  2. Step 2: Convert to fraction form
    847.78/1,170.78 = 645.54/x
  3. Step 3: Cross multiply
    847.78x = 1,170.78 × 645.54
  4. Step 4: Simplify right side
    847.78x = 755,785.32
  5. Step 5: Solve for x
    x = 755,785.32/847.78
  6. Step 6: Final answer
    x = 891.49

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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.