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Finding the Fourth Proportional to 72.35, 99.86 and 57.81

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Solution

The fourth proportional to 72.35, 99.86 and 57.81 is: 79.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.35 : 99.86 = 57.81 : x
  2. Step 2: Convert to fraction form
    72.35/99.86 = 57.81/x
  3. Step 3: Cross multiply
    72.35x = 99.86 × 57.81
  4. Step 4: Simplify right side
    72.35x = 5,772.62
  5. Step 5: Solve for x
    x = 5,772.62/72.35
  6. Step 6: Final answer
    x = 79.79

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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.