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Finding the Fourth Proportional to 428.40, 642.60 and 245.88

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Solution

The fourth proportional to 428.40, 642.60 and 245.88 is: 368.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.40 : 642.60 = 245.88 : x
  2. Step 2: Convert to fraction form
    428.40/642.60 = 245.88/x
  3. Step 3: Cross multiply
    428.40x = 642.60 × 245.88
  4. Step 4: Simplify right side
    428.40x = 158,002.49
  5. Step 5: Solve for x
    x = 158,002.49/428.40
  6. Step 6: Final answer
    x = 368.82

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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.