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Finding the Fourth Proportional to 82.15, 123.23 and 21.28

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Solution

The fourth proportional to 82.15, 123.23 and 21.28 is: 31.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.15 : 123.23 = 21.28 : x
  2. Step 2: Convert to fraction form
    82.15/123.23 = 21.28/x
  3. Step 3: Cross multiply
    82.15x = 123.23 × 21.28
  4. Step 4: Simplify right side
    82.15x = 2,622.19
  5. Step 5: Solve for x
    x = 2,622.19/82.15
  6. Step 6: Final answer
    x = 31.92

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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.