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Finding the Fourth Proportional to 82.66, 123.99 and 21.79

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Solution

The fourth proportional to 82.66, 123.99 and 21.79 is: 32.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.66 : 123.99 = 21.79 : x
  2. Step 2: Convert to fraction form
    82.66/123.99 = 21.79/x
  3. Step 3: Cross multiply
    82.66x = 123.99 × 21.79
  4. Step 4: Simplify right side
    82.66x = 2,701.74
  5. Step 5: Solve for x
    x = 2,701.74/82.66
  6. Step 6: Final answer
    x = 32.69

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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.