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Finding the Fourth Proportional to 105.54, 145.56 and 87.21

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Solution

The fourth proportional to 105.54, 145.56 and 87.21 is: 120.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.54 : 145.56 = 87.21 : x
  2. Step 2: Convert to fraction form
    105.54/145.56 = 87.21/x
  3. Step 3: Cross multiply
    105.54x = 145.56 × 87.21
  4. Step 4: Simplify right side
    105.54x = 12,694.29
  5. Step 5: Solve for x
    x = 12,694.29/105.54
  6. Step 6: Final answer
    x = 120.28

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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.