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Finding the Fourth Proportional to 158.90, 219.31 and 99.91

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Solution

The fourth proportional to 158.90, 219.31 and 99.91 is: 137.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.90 : 219.31 = 99.91 : x
  2. Step 2: Convert to fraction form
    158.90/219.31 = 99.91/x
  3. Step 3: Cross multiply
    158.90x = 219.31 × 99.91
  4. Step 4: Simplify right side
    158.90x = 21,910.46
  5. Step 5: Solve for x
    x = 21,910.46/158.90
  6. Step 6: Final answer
    x = 137.89

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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.