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Finding the Fourth Proportional to 105.67, 145.78 and 66.31

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Solution

The fourth proportional to 105.67, 145.78 and 66.31 is: 91.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.67 : 145.78 = 66.31 : x
  2. Step 2: Convert to fraction form
    105.67/145.78 = 66.31/x
  3. Step 3: Cross multiply
    105.67x = 145.78 × 66.31
  4. Step 4: Simplify right side
    105.67x = 9,666.16
  5. Step 5: Solve for x
    x = 9,666.16/105.67
  6. Step 6: Final answer
    x = 91.47

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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.