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Finding the Fourth Proportional to 428.65, 641.76 and 291.49

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Solution

The fourth proportional to 428.65, 641.76 and 291.49 is: 436.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.65 : 641.76 = 291.49 : x
  2. Step 2: Convert to fraction form
    428.65/641.76 = 291.49/x
  3. Step 3: Cross multiply
    428.65x = 641.76 × 291.49
  4. Step 4: Simplify right side
    428.65x = 187,063.92
  5. Step 5: Solve for x
    x = 187,063.92/428.65
  6. Step 6: Final answer
    x = 436.41

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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.