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Finding the Fourth Proportional to 72.57, 99.86 and 66.77

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Solution

The fourth proportional to 72.57, 99.86 and 66.77 is: 91.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.57 : 99.86 = 66.77 : x
  2. Step 2: Convert to fraction form
    72.57/99.86 = 66.77/x
  3. Step 3: Cross multiply
    72.57x = 99.86 × 66.77
  4. Step 4: Simplify right side
    72.57x = 6,666.82
  5. Step 5: Solve for x
    x = 6,666.82/72.57
  6. Step 6: Final answer
    x = 91.87

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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.