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Finding the Fourth Proportional to 105.66, 145.76 and 72.85

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Solution

The fourth proportional to 105.66, 145.76 and 72.85 is: 100.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.66 : 145.76 = 72.85 : x
  2. Step 2: Convert to fraction form
    105.66/145.76 = 72.85/x
  3. Step 3: Cross multiply
    105.66x = 145.76 × 72.85
  4. Step 4: Simplify right side
    105.66x = 10,618.62
  5. Step 5: Solve for x
    x = 10,618.62/105.66
  6. Step 6: Final answer
    x = 100.50

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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.