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Finding the Fourth Proportional to 780.27, 1,170.81 and 318.39

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Solution

The fourth proportional to 780.27, 1,170.81 and 318.39 is: 477.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.27 : 1,170.81 = 318.39 : x
  2. Step 2: Convert to fraction form
    780.27/1,170.81 = 318.39/x
  3. Step 3: Cross multiply
    780.27x = 1,170.81 × 318.39
  4. Step 4: Simplify right side
    780.27x = 372,774.20
  5. Step 5: Solve for x
    x = 372,774.20/780.27
  6. Step 6: Final answer
    x = 477.75

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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.