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Finding the Fourth Proportional to 858.61, 1,287.91 and 310.66

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Solution

The fourth proportional to 858.61, 1,287.91 and 310.66 is: 465.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.61 : 1,287.91 = 310.66 : x
  2. Step 2: Convert to fraction form
    858.61/1,287.91 = 310.66/x
  3. Step 3: Cross multiply
    858.61x = 1,287.91 × 310.66
  4. Step 4: Simplify right side
    858.61x = 400,105.51
  5. Step 5: Solve for x
    x = 400,105.51/858.61
  6. Step 6: Final answer
    x = 465.99

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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.