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Finding the Fourth Proportional to 780.66, 1,171.40 and 347.72

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Solution

The fourth proportional to 780.66, 1,171.40 and 347.72 is: 521.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.66 : 1,171.40 = 347.72 : x
  2. Step 2: Convert to fraction form
    780.66/1,171.40 = 347.72/x
  3. Step 3: Cross multiply
    780.66x = 1,171.40 × 347.72
  4. Step 4: Simplify right side
    780.66x = 407,311.61
  5. Step 5: Solve for x
    x = 407,311.61/780.66
  6. Step 6: Final answer
    x = 521.75

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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.