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Finding the Fourth Proportional to 491.67, 678.41 and 305.20

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Solution

The fourth proportional to 491.67, 678.41 and 305.20 is: 421.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.67 : 678.41 = 305.20 : x
  2. Step 2: Convert to fraction form
    491.67/678.41 = 305.20/x
  3. Step 3: Cross multiply
    491.67x = 678.41 × 305.20
  4. Step 4: Simplify right side
    491.67x = 207,049.21
  5. Step 5: Solve for x
    x = 207,049.21/491.67
  6. Step 6: Final answer
    x = 421.12

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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.