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Finding the Fourth Proportional to 123.60, 170.68 and 90.80

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Solution

The fourth proportional to 123.60, 170.68 and 90.80 is: 125.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.60 : 170.68 = 90.80 : x
  2. Step 2: Convert to fraction form
    123.60/170.68 = 90.80/x
  3. Step 3: Cross multiply
    123.60x = 170.68 × 90.80
  4. Step 4: Simplify right side
    123.60x = 15,497.74
  5. Step 5: Solve for x
    x = 15,497.74/123.60
  6. Step 6: Final answer
    x = 125.39

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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.