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Finding the Fourth Proportional to 712.20, 982.98 and 645.48

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Solution

The fourth proportional to 712.20, 982.98 and 645.48 is: 890.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.20 : 982.98 = 645.48 : x
  2. Step 2: Convert to fraction form
    712.20/982.98 = 645.48/x
  3. Step 3: Cross multiply
    712.20x = 982.98 × 645.48
  4. Step 4: Simplify right side
    712.20x = 634,493.93
  5. Step 5: Solve for x
    x = 634,493.93/712.20
  6. Step 6: Final answer
    x = 890.89

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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.