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Finding the Fourth Proportional to 127.79, 191.78 and 90.99

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Solution

The fourth proportional to 127.79, 191.78 and 90.99 is: 136.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.79 : 191.78 = 90.99 : x
  2. Step 2: Convert to fraction form
    127.79/191.78 = 90.99/x
  3. Step 3: Cross multiply
    127.79x = 191.78 × 90.99
  4. Step 4: Simplify right side
    127.79x = 17,450.06
  5. Step 5: Solve for x
    x = 17,450.06/127.79
  6. Step 6: Final answer
    x = 136.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.