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Finding the Fourth Proportional to 123.21, 169.85 and 86.25

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Solution

The fourth proportional to 123.21, 169.85 and 86.25 is: 118.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.21 : 169.85 = 86.25 : x
  2. Step 2: Convert to fraction form
    123.21/169.85 = 86.25/x
  3. Step 3: Cross multiply
    123.21x = 169.85 × 86.25
  4. Step 4: Simplify right side
    123.21x = 14,649.13
  5. Step 5: Solve for x
    x = 14,649.13/123.21
  6. Step 6: Final answer
    x = 118.90

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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.