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Finding the Fourth Proportional to 100.26, 138.06 and 87.30

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Solution

The fourth proportional to 100.26, 138.06 and 87.30 is: 120.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.26 : 138.06 = 87.30 : x
  2. Step 2: Convert to fraction form
    100.26/138.06 = 87.30/x
  3. Step 3: Cross multiply
    100.26x = 138.06 × 87.30
  4. Step 4: Simplify right side
    100.26x = 12,052.64
  5. Step 5: Solve for x
    x = 12,052.64/100.26
  6. Step 6: Final answer
    x = 120.21

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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.