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Finding the Fourth Proportional to 858.81, 1,287.39 and 310.68

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Solution

The fourth proportional to 858.81, 1,287.39 and 310.68 is: 465.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.81 : 1,287.39 = 310.68 : x
  2. Step 2: Convert to fraction form
    858.81/1,287.39 = 310.68/x
  3. Step 3: Cross multiply
    858.81x = 1,287.39 × 310.68
  4. Step 4: Simplify right side
    858.81x = 399,966.33
  5. Step 5: Solve for x
    x = 399,966.33/858.81
  6. Step 6: Final answer
    x = 465.72

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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.