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Finding the Fourth Proportional to 105.15, 145.09 and 61.51

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Solution

The fourth proportional to 105.15, 145.09 and 61.51 is: 84.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.15 : 145.09 = 61.51 : x
  2. Step 2: Convert to fraction form
    105.15/145.09 = 61.51/x
  3. Step 3: Cross multiply
    105.15x = 145.09 × 61.51
  4. Step 4: Simplify right side
    105.15x = 8,924.20
  5. Step 5: Solve for x
    x = 8,924.20/105.15
  6. Step 6: Final answer
    x = 84.87

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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.