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Finding the Fourth Proportional to 840.65, 1,261.11 and 378.59

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Solution

The fourth proportional to 840.65, 1,261.11 and 378.59 is: 567.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.65 : 1,261.11 = 378.59 : x
  2. Step 2: Convert to fraction form
    840.65/1,261.11 = 378.59/x
  3. Step 3: Cross multiply
    840.65x = 1,261.11 × 378.59
  4. Step 4: Simplify right side
    840.65x = 477,443.63
  5. Step 5: Solve for x
    x = 477,443.63/840.65
  6. Step 6: Final answer
    x = 567.95

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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.