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Finding the Fourth Proportional to 105.12, 145.08 and 61.45

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Solution

The fourth proportional to 105.12, 145.08 and 61.45 is: 84.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.12 : 145.08 = 61.45 : x
  2. Step 2: Convert to fraction form
    105.12/145.08 = 61.45/x
  3. Step 3: Cross multiply
    105.12x = 145.08 × 61.45
  4. Step 4: Simplify right side
    105.12x = 8,914.80
  5. Step 5: Solve for x
    x = 8,914.80/105.12
  6. Step 6: Final answer
    x = 84.81

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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.