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Finding the Fourth Proportional to 858.08, 1,287.18 and 310.40

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Solution

The fourth proportional to 858.08, 1,287.18 and 310.40 is: 465.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.08 : 1,287.18 = 310.40 : x
  2. Step 2: Convert to fraction form
    858.08/1,287.18 = 310.40/x
  3. Step 3: Cross multiply
    858.08x = 1,287.18 × 310.40
  4. Step 4: Simplify right side
    858.08x = 399,540.67
  5. Step 5: Solve for x
    x = 399,540.67/858.08
  6. Step 6: Final answer
    x = 465.62

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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.