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Finding the Fourth Proportional to 428.57, 643.22 and 343.61

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Solution

The fourth proportional to 428.57, 643.22 and 343.61 is: 515.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.57 : 643.22 = 343.61 : x
  2. Step 2: Convert to fraction form
    428.57/643.22 = 343.61/x
  3. Step 3: Cross multiply
    428.57x = 643.22 × 343.61
  4. Step 4: Simplify right side
    428.57x = 221,015.11
  5. Step 5: Solve for x
    x = 221,015.11/428.57
  6. Step 6: Final answer
    x = 515.70

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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.