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Finding the Fourth Proportional to 840.68, 1,261.26 and 407.76

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Solution

The fourth proportional to 840.68, 1,261.26 and 407.76 is: 611.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.68 : 1,261.26 = 407.76 : x
  2. Step 2: Convert to fraction form
    840.68/1,261.26 = 407.76/x
  3. Step 3: Cross multiply
    840.68x = 1,261.26 × 407.76
  4. Step 4: Simplify right side
    840.68x = 514,291.38
  5. Step 5: Solve for x
    x = 514,291.38/840.68
  6. Step 6: Final answer
    x = 611.76

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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.