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Finding the Fourth Proportional to 100.27, 138.21 and 87.10

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Solution

The fourth proportional to 100.27, 138.21 and 87.10 is: 120.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.27 : 138.21 = 87.10 : x
  2. Step 2: Convert to fraction form
    100.27/138.21 = 87.10/x
  3. Step 3: Cross multiply
    100.27x = 138.21 × 87.10
  4. Step 4: Simplify right side
    100.27x = 12,038.09
  5. Step 5: Solve for x
    x = 12,038.09/100.27
  6. Step 6: Final answer
    x = 120.06

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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.