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Finding the Fourth Proportional to 72.45, 99.96 and 51.78

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Solution

The fourth proportional to 72.45, 99.96 and 51.78 is: 71.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.45 : 99.96 = 51.78 : x
  2. Step 2: Convert to fraction form
    72.45/99.96 = 51.78/x
  3. Step 3: Cross multiply
    72.45x = 99.96 × 51.78
  4. Step 4: Simplify right side
    72.45x = 5,175.93
  5. Step 5: Solve for x
    x = 5,175.93/72.45
  6. Step 6: Final answer
    x = 71.44

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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.