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Finding the Fourth Proportional to 71.87, 106.87 and 69.70

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Solution

The fourth proportional to 71.87, 106.87 and 69.70 is: 103.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.87 : 106.87 = 69.70 : x
  2. Step 2: Convert to fraction form
    71.87/106.87 = 69.70/x
  3. Step 3: Cross multiply
    71.87x = 106.87 × 69.70
  4. Step 4: Simplify right side
    71.87x = 7,448.84
  5. Step 5: Solve for x
    x = 7,448.84/71.87
  6. Step 6: Final answer
    x = 103.64

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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.