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Finding the Fourth Proportional to 428.36, 642.32 and 255.08

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Solution

The fourth proportional to 428.36, 642.32 and 255.08 is: 382.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.36 : 642.32 = 255.08 : x
  2. Step 2: Convert to fraction form
    428.36/642.32 = 255.08/x
  3. Step 3: Cross multiply
    428.36x = 642.32 × 255.08
  4. Step 4: Simplify right side
    428.36x = 163,842.99
  5. Step 5: Solve for x
    x = 163,842.99/428.36
  6. Step 6: Final answer
    x = 382.49

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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.