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Finding the Fourth Proportional to 780.63, 1,171.39 and 347.78

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Solution

The fourth proportional to 780.63, 1,171.39 and 347.78 is: 521.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.63 : 1,171.39 = 347.78 : x
  2. Step 2: Convert to fraction form
    780.63/1,171.39 = 347.78/x
  3. Step 3: Cross multiply
    780.63x = 1,171.39 × 347.78
  4. Step 4: Simplify right side
    780.63x = 407,386.01
  5. Step 5: Solve for x
    x = 407,386.01/780.63
  6. Step 6: Final answer
    x = 521.87

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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.