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Finding the Fourth Proportional to 70.35, 105.48 and 31.80

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Solution

The fourth proportional to 70.35, 105.48 and 31.80 is: 47.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.35 : 105.48 = 31.80 : x
  2. Step 2: Convert to fraction form
    70.35/105.48 = 31.80/x
  3. Step 3: Cross multiply
    70.35x = 105.48 × 31.80
  4. Step 4: Simplify right side
    70.35x = 3,354.26
  5. Step 5: Solve for x
    x = 3,354.26/70.35
  6. Step 6: Final answer
    x = 47.68

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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.