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Finding the Fourth Proportional to 66.86, 99.81 and 64.61

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Solution

The fourth proportional to 66.86, 99.81 and 64.61 is: 96.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.86 : 99.81 = 64.61 : x
  2. Step 2: Convert to fraction form
    66.86/99.81 = 64.61/x
  3. Step 3: Cross multiply
    66.86x = 99.81 × 64.61
  4. Step 4: Simplify right side
    66.86x = 6,448.72
  5. Step 5: Solve for x
    x = 6,448.72/66.86
  6. Step 6: Final answer
    x = 96.45

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.