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Finding the Fourth Proportional to 428.76, 643.16 and 168.74

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Solution

The fourth proportional to 428.76, 643.16 and 168.74 is: 253.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.76 : 643.16 = 168.74 : x
  2. Step 2: Convert to fraction form
    428.76/643.16 = 168.74/x
  3. Step 3: Cross multiply
    428.76x = 643.16 × 168.74
  4. Step 4: Simplify right side
    428.76x = 108,526.82
  5. Step 5: Solve for x
    x = 108,526.82/428.76
  6. Step 6: Final answer
    x = 253.12

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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.