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Finding the Fourth Proportional to 123.81, 171.33 and 99.51

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Solution

The fourth proportional to 123.81, 171.33 and 99.51 is: 137.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.81 : 171.33 = 99.51 : x
  2. Step 2: Convert to fraction form
    123.81/171.33 = 99.51/x
  3. Step 3: Cross multiply
    123.81x = 171.33 × 99.51
  4. Step 4: Simplify right side
    123.81x = 17,049.05
  5. Step 5: Solve for x
    x = 17,049.05/123.81
  6. Step 6: Final answer
    x = 137.70

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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.