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Finding the Fourth Proportional to 72.12, 108.57 and 61.68

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Solution

The fourth proportional to 72.12, 108.57 and 61.68 is: 92.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.12 : 108.57 = 61.68 : x
  2. Step 2: Convert to fraction form
    72.12/108.57 = 61.68/x
  3. Step 3: Cross multiply
    72.12x = 108.57 × 61.68
  4. Step 4: Simplify right side
    72.12x = 6,696.60
  5. Step 5: Solve for x
    x = 6,696.60/72.12
  6. Step 6: Final answer
    x = 92.85

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.