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Finding the Fourth Proportional to 123.89, 170.89 and 74.72

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Solution

The fourth proportional to 123.89, 170.89 and 74.72 is: 103.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.89 : 170.89 = 74.72 : x
  2. Step 2: Convert to fraction form
    123.89/170.89 = 74.72/x
  3. Step 3: Cross multiply
    123.89x = 170.89 × 74.72
  4. Step 4: Simplify right side
    123.89x = 12,767.86
  5. Step 5: Solve for x
    x = 12,767.86/123.89
  6. Step 6: Final answer
    x = 103.06

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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.