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Finding the Fourth Proportional to 491.43, 678.49 and 305.12

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Solution

The fourth proportional to 491.43, 678.49 and 305.12 is: 421.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.43 : 678.49 = 305.12 : x
  2. Step 2: Convert to fraction form
    491.43/678.49 = 305.12/x
  3. Step 3: Cross multiply
    491.43x = 678.49 × 305.12
  4. Step 4: Simplify right side
    491.43x = 207,020.87
  5. Step 5: Solve for x
    x = 207,020.87/491.43
  6. Step 6: Final answer
    x = 421.26

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.