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Finding the Fourth Proportional to 491.81, 678.78 and 317.25

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Solution

The fourth proportional to 491.81, 678.78 and 317.25 is: 437.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.81 : 678.78 = 317.25 : x
  2. Step 2: Convert to fraction form
    491.81/678.78 = 317.25/x
  3. Step 3: Cross multiply
    491.81x = 678.78 × 317.25
  4. Step 4: Simplify right side
    491.81x = 215,342.96
  5. Step 5: Solve for x
    x = 215,342.96/491.81
  6. Step 6: Final answer
    x = 437.86

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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.