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Finding the Fourth Proportional to 428.84, 645.09 and 388.75

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Solution

The fourth proportional to 428.84, 645.09 and 388.75 is: 584.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.84 : 645.09 = 388.75 : x
  2. Step 2: Convert to fraction form
    428.84/645.09 = 388.75/x
  3. Step 3: Cross multiply
    428.84x = 645.09 × 388.75
  4. Step 4: Simplify right side
    428.84x = 250,773.57
  5. Step 5: Solve for x
    x = 250,773.57/428.84
  6. Step 6: Final answer
    x = 584.77

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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.