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Finding the Fourth Proportional to 71.12, 106.68 and 69.78

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Solution

The fourth proportional to 71.12, 106.68 and 69.78 is: 104.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.12 : 106.68 = 69.78 : x
  2. Step 2: Convert to fraction form
    71.12/106.68 = 69.78/x
  3. Step 3: Cross multiply
    71.12x = 106.68 × 69.78
  4. Step 4: Simplify right side
    71.12x = 7,444.13
  5. Step 5: Solve for x
    x = 7,444.13/71.12
  6. Step 6: Final answer
    x = 104.67

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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.