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Finding the Fourth Proportional to 105.12, 145.08 and 65.81

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Solution

The fourth proportional to 105.12, 145.08 and 65.81 is: 90.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.12 : 145.08 = 65.81 : x
  2. Step 2: Convert to fraction form
    105.12/145.08 = 65.81/x
  3. Step 3: Cross multiply
    105.12x = 145.08 × 65.81
  4. Step 4: Simplify right side
    105.12x = 9,548.08
  5. Step 5: Solve for x
    x = 9,548.08/105.12
  6. Step 6: Final answer
    x = 90.83

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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.