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Finding the Fourth Proportional to 90.84, 126.09 and 87.32

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Solution

The fourth proportional to 90.84, 126.09 and 87.32 is: 121.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.84 : 126.09 = 87.32 : x
  2. Step 2: Convert to fraction form
    90.84/126.09 = 87.32/x
  3. Step 3: Cross multiply
    90.84x = 126.09 × 87.32
  4. Step 4: Simplify right side
    90.84x = 11,010.18
  5. Step 5: Solve for x
    x = 11,010.18/90.84
  6. Step 6: Final answer
    x = 121.20

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.