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Finding the Fourth Proportional to 427.12, 640.76 and 221.63

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Solution

The fourth proportional to 427.12, 640.76 and 221.63 is: 332.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.12 : 640.76 = 221.63 : x
  2. Step 2: Convert to fraction form
    427.12/640.76 = 221.63/x
  3. Step 3: Cross multiply
    427.12x = 640.76 × 221.63
  4. Step 4: Simplify right side
    427.12x = 142,012.18
  5. Step 5: Solve for x
    x = 142,012.18/427.12
  6. Step 6: Final answer
    x = 332.49

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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.