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Finding the Fourth Proportional to 100.34, 138.50 and 79.68

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Solution

The fourth proportional to 100.34, 138.50 and 79.68 is: 109.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.34 : 138.50 = 79.68 : x
  2. Step 2: Convert to fraction form
    100.34/138.50 = 79.68/x
  3. Step 3: Cross multiply
    100.34x = 138.50 × 79.68
  4. Step 4: Simplify right side
    100.34x = 11,035.28
  5. Step 5: Solve for x
    x = 11,035.28/100.34
  6. Step 6: Final answer
    x = 109.98

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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.