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Finding the Fourth Proportional to 486.55, 671.90 and 312.20

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Solution

The fourth proportional to 486.55, 671.90 and 312.20 is: 431.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.55 : 671.90 = 312.20 : x
  2. Step 2: Convert to fraction form
    486.55/671.90 = 312.20/x
  3. Step 3: Cross multiply
    486.55x = 671.90 × 312.20
  4. Step 4: Simplify right side
    486.55x = 209,764.78
  5. Step 5: Solve for x
    x = 209,764.78/486.55
  6. Step 6: Final answer
    x = 431.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.