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Finding the Fourth Proportional to 212.39, 318.49 and 82.45

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Solution

The fourth proportional to 212.39, 318.49 and 82.45 is: 123.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.39 : 318.49 = 82.45 : x
  2. Step 2: Convert to fraction form
    212.39/318.49 = 82.45/x
  3. Step 3: Cross multiply
    212.39x = 318.49 × 82.45
  4. Step 4: Simplify right side
    212.39x = 26,260.64
  5. Step 5: Solve for x
    x = 26,260.64/212.39
  6. Step 6: Final answer
    x = 123.64

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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.