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Finding the Fourth Proportional to 858.72, 1,288.20 and 310.80

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Solution

The fourth proportional to 858.72, 1,288.20 and 310.80 is: 466.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.72 : 1,288.20 = 310.80 : x
  2. Step 2: Convert to fraction form
    858.72/1,288.20 = 310.80/x
  3. Step 3: Cross multiply
    858.72x = 1,288.20 × 310.80
  4. Step 4: Simplify right side
    858.72x = 400,372.56
  5. Step 5: Solve for x
    x = 400,372.56/858.72
  6. Step 6: Final answer
    x = 466.24

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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.