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Finding the Fourth Proportional to 111.71, 154.09 and 90.99

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Solution

The fourth proportional to 111.71, 154.09 and 90.99 is: 125.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.71 : 154.09 = 90.99 : x
  2. Step 2: Convert to fraction form
    111.71/154.09 = 90.99/x
  3. Step 3: Cross multiply
    111.71x = 154.09 × 90.99
  4. Step 4: Simplify right side
    111.71x = 14,020.42
  5. Step 5: Solve for x
    x = 14,020.42/111.71
  6. Step 6: Final answer
    x = 125.50

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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.