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Finding the Fourth Proportional to 71.72, 99.14 and 64.36

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Solution

The fourth proportional to 71.72, 99.14 and 64.36 is: 88.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.72 : 99.14 = 64.36 : x
  2. Step 2: Convert to fraction form
    71.72/99.14 = 64.36/x
  3. Step 3: Cross multiply
    71.72x = 99.14 × 64.36
  4. Step 4: Simplify right side
    71.72x = 6,380.65
  5. Step 5: Solve for x
    x = 6,380.65/71.72
  6. Step 6: Final answer
    x = 88.97

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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.