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Finding the Fourth Proportional to 90.54, 123.80 and 87.18

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Solution

The fourth proportional to 90.54, 123.80 and 87.18 is: 119.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.54 : 123.80 = 87.18 : x
  2. Step 2: Convert to fraction form
    90.54/123.80 = 87.18/x
  3. Step 3: Cross multiply
    90.54x = 123.80 × 87.18
  4. Step 4: Simplify right side
    90.54x = 10,792.45
  5. Step 5: Solve for x
    x = 10,792.45/90.54
  6. Step 6: Final answer
    x = 119.20

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.