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Finding the Fourth Proportional to 100.88, 138.26 and 99.72

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Solution

The fourth proportional to 100.88, 138.26 and 99.72 is: 136.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.88 : 138.26 = 99.72 : x
  2. Step 2: Convert to fraction form
    100.88/138.26 = 99.72/x
  3. Step 3: Cross multiply
    100.88x = 138.26 × 99.72
  4. Step 4: Simplify right side
    100.88x = 13,787.29
  5. Step 5: Solve for x
    x = 13,787.29/100.88
  6. Step 6: Final answer
    x = 136.67

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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.