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Finding the Fourth Proportional to 878.96, 1,212.36 and 645.68

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Solution

The fourth proportional to 878.96, 1,212.36 and 645.68 is: 890.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.96 : 1,212.36 = 645.68 : x
  2. Step 2: Convert to fraction form
    878.96/1,212.36 = 645.68/x
  3. Step 3: Cross multiply
    878.96x = 1,212.36 × 645.68
  4. Step 4: Simplify right side
    878.96x = 782,796.60
  5. Step 5: Solve for x
    x = 782,796.60/878.96
  6. Step 6: Final answer
    x = 890.59

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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.