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Finding the Fourth Proportional to 786.40, 1,179.30 and 478.64

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Solution

The fourth proportional to 786.40, 1,179.30 and 478.64 is: 717.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.40 : 1,179.30 = 478.64 : x
  2. Step 2: Convert to fraction form
    786.40/1,179.30 = 478.64/x
  3. Step 3: Cross multiply
    786.40x = 1,179.30 × 478.64
  4. Step 4: Simplify right side
    786.40x = 564,460.15
  5. Step 5: Solve for x
    x = 564,460.15/786.40
  6. Step 6: Final answer
    x = 717.78

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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.