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Finding the Fourth Proportional to 99.72, 137.61 and 87.48

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Solution

The fourth proportional to 99.72, 137.61 and 87.48 is: 120.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.72 : 137.61 = 87.48 : x
  2. Step 2: Convert to fraction form
    99.72/137.61 = 87.48/x
  3. Step 3: Cross multiply
    99.72x = 137.61 × 87.48
  4. Step 4: Simplify right side
    99.72x = 12,038.12
  5. Step 5: Solve for x
    x = 12,038.12/99.72
  6. Step 6: Final answer
    x = 120.72

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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.