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Finding the Fourth Proportional to 105.72, 145.21 and 87.26

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Solution

The fourth proportional to 105.72, 145.21 and 87.26 is: 119.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.72 : 145.21 = 87.26 : x
  2. Step 2: Convert to fraction form
    105.72/145.21 = 87.26/x
  3. Step 3: Cross multiply
    105.72x = 145.21 × 87.26
  4. Step 4: Simplify right side
    105.72x = 12,670.30
  5. Step 5: Solve for x
    x = 12,670.30/105.72
  6. Step 6: Final answer
    x = 119.85

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.