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Finding the Fourth Proportional to 428.46, 641.75 and 326.40

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Solution

The fourth proportional to 428.46, 641.75 and 326.40 is: 488.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.46 : 641.75 = 326.40 : x
  2. Step 2: Convert to fraction form
    428.46/641.75 = 326.40/x
  3. Step 3: Cross multiply
    428.46x = 641.75 × 326.40
  4. Step 4: Simplify right side
    428.46x = 209,465.57
  5. Step 5: Solve for x
    x = 209,465.57/428.46
  6. Step 6: Final answer
    x = 488.88

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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.