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Finding the Fourth Proportional to 72.11, 99.51 and 39.36

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Solution

The fourth proportional to 72.11, 99.51 and 39.36 is: 54.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.11 : 99.51 = 39.36 : x
  2. Step 2: Convert to fraction form
    72.11/99.51 = 39.36/x
  3. Step 3: Cross multiply
    72.11x = 99.51 × 39.36
  4. Step 4: Simplify right side
    72.11x = 3,916.38
  5. Step 5: Solve for x
    x = 3,916.38/72.11
  6. Step 6: Final answer
    x = 54.31

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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.