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Finding the Fourth Proportional to 780.79, 1,170.80 and 318.38

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Solution

The fourth proportional to 780.79, 1,170.80 and 318.38 is: 477.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.79 : 1,170.80 = 318.38 : x
  2. Step 2: Convert to fraction form
    780.79/1,170.80 = 318.38/x
  3. Step 3: Cross multiply
    780.79x = 1,170.80 × 318.38
  4. Step 4: Simplify right side
    780.79x = 372,761.43
  5. Step 5: Solve for x
    x = 372,761.43/780.79
  6. Step 6: Final answer
    x = 477.42

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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.