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Finding the Fourth Proportional to 858.70, 1,287.96 and 310.78

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Solution

The fourth proportional to 858.70, 1,287.96 and 310.78 is: 466.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.70 : 1,287.96 = 310.78 : x
  2. Step 2: Convert to fraction form
    858.70/1,287.96 = 310.78/x
  3. Step 3: Cross multiply
    858.70x = 1,287.96 × 310.78
  4. Step 4: Simplify right side
    858.70x = 400,272.21
  5. Step 5: Solve for x
    x = 400,272.21/858.70
  6. Step 6: Final answer
    x = 466.14

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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.