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Finding the Fourth Proportional to 842.47, 1,257.32 and 820.60

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Solution

The fourth proportional to 842.47, 1,257.32 and 820.60 is: 1,224.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.47 : 1,257.32 = 820.60 : x
  2. Step 2: Convert to fraction form
    842.47/1,257.32 = 820.60/x
  3. Step 3: Cross multiply
    842.47x = 1,257.32 × 820.60
  4. Step 4: Simplify right side
    842.47x = 1,031,756.79
  5. Step 5: Solve for x
    x = 1,031,756.79/842.47
  6. Step 6: Final answer
    x = 1,224.68

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.