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Finding the Fourth Proportional to 491.69, 678.42 and 305.19

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Solution

The fourth proportional to 491.69, 678.42 and 305.19 is: 421.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.69 : 678.42 = 305.19 : x
  2. Step 2: Convert to fraction form
    491.69/678.42 = 305.19/x
  3. Step 3: Cross multiply
    491.69x = 678.42 × 305.19
  4. Step 4: Simplify right side
    491.69x = 207,042.08
  5. Step 5: Solve for x
    x = 207,042.08/491.69
  6. Step 6: Final answer
    x = 421.09

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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.