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Finding the Fourth Proportional to 858.60, 1,287.96 and 310.79

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Solution

The fourth proportional to 858.60, 1,287.96 and 310.79 is: 466.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.60 : 1,287.96 = 310.79 : x
  2. Step 2: Convert to fraction form
    858.60/1,287.96 = 310.79/x
  3. Step 3: Cross multiply
    858.60x = 1,287.96 × 310.79
  4. Step 4: Simplify right side
    858.60x = 400,277.09
  5. Step 5: Solve for x
    x = 400,277.09/858.60
  6. Step 6: Final answer
    x = 466.20

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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.