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Finding the Fourth Proportional to 99.79, 149.65 and 90.61

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Solution

The fourth proportional to 99.79, 149.65 and 90.61 is: 135.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.79 : 149.65 = 90.61 : x
  2. Step 2: Convert to fraction form
    99.79/149.65 = 90.61/x
  3. Step 3: Cross multiply
    99.79x = 149.65 × 90.61
  4. Step 4: Simplify right side
    99.79x = 13,559.79
  5. Step 5: Solve for x
    x = 13,559.79/99.79
  6. Step 6: Final answer
    x = 135.88

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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.