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Finding the Fourth Proportional to 71.81, 99.10 and 39.06

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Solution

The fourth proportional to 71.81, 99.10 and 39.06 is: 53.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.81 : 99.10 = 39.06 : x
  2. Step 2: Convert to fraction form
    71.81/99.10 = 39.06/x
  3. Step 3: Cross multiply
    71.81x = 99.10 × 39.06
  4. Step 4: Simplify right side
    71.81x = 3,870.85
  5. Step 5: Solve for x
    x = 3,870.85/71.81
  6. Step 6: Final answer
    x = 53.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.