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Finding the Fourth Proportional to 428.84, 643.10 and 209.33

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Solution

The fourth proportional to 428.84, 643.10 and 209.33 is: 313.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.84 : 643.10 = 209.33 : x
  2. Step 2: Convert to fraction form
    428.84/643.10 = 209.33/x
  3. Step 3: Cross multiply
    428.84x = 643.10 × 209.33
  4. Step 4: Simplify right side
    428.84x = 134,615.86
  5. Step 5: Solve for x
    x = 134,615.86/428.84
  6. Step 6: Final answer
    x = 313.91

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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.