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Finding the Fourth Proportional to 428.49, 643.80 and 274.49

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Solution

The fourth proportional to 428.49, 643.80 and 274.49 is: 412.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.49 : 643.80 = 274.49 : x
  2. Step 2: Convert to fraction form
    428.49/643.80 = 274.49/x
  3. Step 3: Cross multiply
    428.49x = 643.80 × 274.49
  4. Step 4: Simplify right side
    428.49x = 176,716.66
  5. Step 5: Solve for x
    x = 176,716.66/428.49
  6. Step 6: Final answer
    x = 412.42

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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.