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Finding the Fourth Proportional to 486.78, 729.75 and 212.66

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Solution

The fourth proportional to 486.78, 729.75 and 212.66 is: 318.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.78 : 729.75 = 212.66 : x
  2. Step 2: Convert to fraction form
    486.78/729.75 = 212.66/x
  3. Step 3: Cross multiply
    486.78x = 729.75 × 212.66
  4. Step 4: Simplify right side
    486.78x = 155,184.99
  5. Step 5: Solve for x
    x = 155,184.99/486.78
  6. Step 6: Final answer
    x = 318.80

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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.