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Finding the Fourth Proportional to 100.69, 138.70 and 83.18

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Solution

The fourth proportional to 100.69, 138.70 and 83.18 is: 114.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.69 : 138.70 = 83.18 : x
  2. Step 2: Convert to fraction form
    100.69/138.70 = 83.18/x
  3. Step 3: Cross multiply
    100.69x = 138.70 × 83.18
  4. Step 4: Simplify right side
    100.69x = 11,537.07
  5. Step 5: Solve for x
    x = 11,537.07/100.69
  6. Step 6: Final answer
    x = 114.58

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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.