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Finding the Fourth Proportional to 82.15, 123.32 and 77.90

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Solution

The fourth proportional to 82.15, 123.32 and 77.90 is: 116.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.15 : 123.32 = 77.90 : x
  2. Step 2: Convert to fraction form
    82.15/123.32 = 77.90/x
  3. Step 3: Cross multiply
    82.15x = 123.32 × 77.90
  4. Step 4: Simplify right side
    82.15x = 9,606.21
  5. Step 5: Solve for x
    x = 9,606.21/82.15
  6. Step 6: Final answer
    x = 116.94

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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.