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Finding the Fourth Proportional to 780.81, 1,171.38 and 318.59

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Solution

The fourth proportional to 780.81, 1,171.38 and 318.59 is: 477.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.81 : 1,171.38 = 318.59 : x
  2. Step 2: Convert to fraction form
    780.81/1,171.38 = 318.59/x
  3. Step 3: Cross multiply
    780.81x = 1,171.38 × 318.59
  4. Step 4: Simplify right side
    780.81x = 373,192.88
  5. Step 5: Solve for x
    x = 373,192.88/780.81
  6. Step 6: Final answer
    x = 477.96

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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.