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Finding the Fourth Proportional to 428.70, 642.78 and 223.02

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Solution

The fourth proportional to 428.70, 642.78 and 223.02 is: 334.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.70 : 642.78 = 223.02 : x
  2. Step 2: Convert to fraction form
    428.70/642.78 = 223.02/x
  3. Step 3: Cross multiply
    428.70x = 642.78 × 223.02
  4. Step 4: Simplify right side
    428.70x = 143,352.80
  5. Step 5: Solve for x
    x = 143,352.80/428.70
  6. Step 6: Final answer
    x = 334.39

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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.