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Finding the Fourth Proportional to 486.70, 671.28 and 311.95

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Solution

The fourth proportional to 486.70, 671.28 and 311.95 is: 430.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.70 : 671.28 = 311.95 : x
  2. Step 2: Convert to fraction form
    486.70/671.28 = 311.95/x
  3. Step 3: Cross multiply
    486.70x = 671.28 × 311.95
  4. Step 4: Simplify right side
    486.70x = 209,405.80
  5. Step 5: Solve for x
    x = 209,405.80/486.70
  6. Step 6: Final answer
    x = 430.26

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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.