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Finding the Fourth Proportional to 860.78, 1,290.62 and 397.93

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Solution

The fourth proportional to 860.78, 1,290.62 and 397.93 is: 596.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.78 : 1,290.62 = 397.93 : x
  2. Step 2: Convert to fraction form
    860.78/1,290.62 = 397.93/x
  3. Step 3: Cross multiply
    860.78x = 1,290.62 × 397.93
  4. Step 4: Simplify right side
    860.78x = 513,576.42
  5. Step 5: Solve for x
    x = 513,576.42/860.78
  6. Step 6: Final answer
    x = 596.64

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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.