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Finding the Fourth Proportional to 780.99, 1,171.15 and 318.45

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Solution

The fourth proportional to 780.99, 1,171.15 and 318.45 is: 477.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.99 : 1,171.15 = 318.45 : x
  2. Step 2: Convert to fraction form
    780.99/1,171.15 = 318.45/x
  3. Step 3: Cross multiply
    780.99x = 1,171.15 × 318.45
  4. Step 4: Simplify right side
    780.99x = 372,952.72
  5. Step 5: Solve for x
    x = 372,952.72/780.99
  6. Step 6: Final answer
    x = 477.54

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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.