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Finding the Fourth Proportional to 1,380.78, 2,071.17 and 407.57

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Solution

The fourth proportional to 1,380.78, 2,071.17 and 407.57 is: 611.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.78 : 2,071.17 = 407.57 : x
  2. Step 2: Convert to fraction form
    1,380.78/2,071.17 = 407.57/x
  3. Step 3: Cross multiply
    1,380.78x = 2,071.17 × 407.57
  4. Step 4: Simplify right side
    1,380.78x = 844,136.40
  5. Step 5: Solve for x
    x = 844,136.40/1,380.78
  6. Step 6: Final answer
    x = 611.35

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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.