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Finding the Fourth Proportional to 431.80, 647.70 and 311.20

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Solution

The fourth proportional to 431.80, 647.70 and 311.20 is: 466.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.80 : 647.70 = 311.20 : x
  2. Step 2: Convert to fraction form
    431.80/647.70 = 311.20/x
  3. Step 3: Cross multiply
    431.80x = 647.70 × 311.20
  4. Step 4: Simplify right side
    431.80x = 201,564.24
  5. Step 5: Solve for x
    x = 201,564.24/431.80
  6. Step 6: Final answer
    x = 466.80

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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.