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Finding the Fourth Proportional to 491.49, 678.11 and 393.21

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Solution

The fourth proportional to 491.49, 678.11 and 393.21 is: 542.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.49 : 678.11 = 393.21 : x
  2. Step 2: Convert to fraction form
    491.49/678.11 = 393.21/x
  3. Step 3: Cross multiply
    491.49x = 678.11 × 393.21
  4. Step 4: Simplify right side
    491.49x = 266,637.67
  5. Step 5: Solve for x
    x = 266,637.67/491.49
  6. Step 6: Final answer
    x = 542.51

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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.