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Finding the Fourth Proportional to 70.22, 105.31 and 39.80

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Solution

The fourth proportional to 70.22, 105.31 and 39.80 is: 59.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.22 : 105.31 = 39.80 : x
  2. Step 2: Convert to fraction form
    70.22/105.31 = 39.80/x
  3. Step 3: Cross multiply
    70.22x = 105.31 × 39.80
  4. Step 4: Simplify right side
    70.22x = 4,191.34
  5. Step 5: Solve for x
    x = 4,191.34/70.22
  6. Step 6: Final answer
    x = 59.69

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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.