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Finding the Fourth Proportional to 73.21, 109.61 and 71.78

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Solution

The fourth proportional to 73.21, 109.61 and 71.78 is: 107.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    73.21 : 109.61 = 71.78 : x
  2. Step 2: Convert to fraction form
    73.21/109.61 = 71.78/x
  3. Step 3: Cross multiply
    73.21x = 109.61 × 71.78
  4. Step 4: Simplify right side
    73.21x = 7,867.81
  5. Step 5: Solve for x
    x = 7,867.81/73.21
  6. Step 6: Final answer
    x = 107.47

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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.