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Finding the Fourth Proportional to 428, 640.61 and 222.28

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Solution

The fourth proportional to 428, 640.61 and 222.28 is: 332.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    428 : 640.61 = 222.28 : x
  2. Step 2: Convert to fraction form
    428/640.61 = 222.28/x
  3. Step 3: Cross multiply
    428x = 640.61 × 222.28
  4. Step 4: Simplify right side
    428x = 142,391.59
  5. Step 5: Solve for x
    x = 142,391.59/428
  6. Step 6: Final answer
    x = 332.69

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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.