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Finding the Fourth Proportional to 428.50, 642.75 and 200.50

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Solution

The fourth proportional to 428.50, 642.75 and 200.50 is: 300.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.50 : 642.75 = 200.50 : x
  2. Step 2: Convert to fraction form
    428.50/642.75 = 200.50/x
  3. Step 3: Cross multiply
    428.50x = 642.75 × 200.50
  4. Step 4: Simplify right side
    428.50x = 128,871.38
  5. Step 5: Solve for x
    x = 128,871.38/428.50
  6. Step 6: Final answer
    x = 300.75

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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.