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Finding the Fourth Proportional to 780.98, 1,171.43 and 318.74

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Solution

The fourth proportional to 780.98, 1,171.43 and 318.74 is: 478.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.98 : 1,171.43 = 318.74 : x
  2. Step 2: Convert to fraction form
    780.98/1,171.43 = 318.74/x
  3. Step 3: Cross multiply
    780.98x = 1,171.43 × 318.74
  4. Step 4: Simplify right side
    780.98x = 373,375.34
  5. Step 5: Solve for x
    x = 373,375.34/780.98
  6. Step 6: Final answer
    x = 478.09

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.