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Finding the Fourth Proportional to 858.39, 1,287.28 and 310.47

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Solution

The fourth proportional to 858.39, 1,287.28 and 310.47 is: 465.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.39 : 1,287.28 = 310.47 : x
  2. Step 2: Convert to fraction form
    858.39/1,287.28 = 310.47/x
  3. Step 3: Cross multiply
    858.39x = 1,287.28 × 310.47
  4. Step 4: Simplify right side
    858.39x = 399,661.82
  5. Step 5: Solve for x
    x = 399,661.82/858.39
  6. Step 6: Final answer
    x = 465.59

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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.