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Finding the Fourth Proportional to 840.84, 1,261.58 and 407.72

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Solution

The fourth proportional to 840.84, 1,261.58 and 407.72 is: 611.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.84 : 1,261.58 = 407.72 : x
  2. Step 2: Convert to fraction form
    840.84/1,261.58 = 407.72/x
  3. Step 3: Cross multiply
    840.84x = 1,261.58 × 407.72
  4. Step 4: Simplify right side
    840.84x = 514,371.40
  5. Step 5: Solve for x
    x = 514,371.40/840.84
  6. Step 6: Final answer
    x = 611.74

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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.