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Finding the Fourth Proportional to 71.82, 99.15 and 64.81

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Solution

The fourth proportional to 71.82, 99.15 and 64.81 is: 89.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.82 : 99.15 = 64.81 : x
  2. Step 2: Convert to fraction form
    71.82/99.15 = 64.81/x
  3. Step 3: Cross multiply
    71.82x = 99.15 × 64.81
  4. Step 4: Simplify right side
    71.82x = 6,425.79
  5. Step 5: Solve for x
    x = 6,425.79/71.82
  6. Step 6: Final answer
    x = 89.47

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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.