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Finding the Fourth Proportional to 858.87, 1,290.72 and 512.28

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Solution

The fourth proportional to 858.87, 1,290.72 and 512.28 is: 769.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.87 : 1,290.72 = 512.28 : x
  2. Step 2: Convert to fraction form
    858.87/1,290.72 = 512.28/x
  3. Step 3: Cross multiply
    858.87x = 1,290.72 × 512.28
  4. Step 4: Simplify right side
    858.87x = 661,210.04
  5. Step 5: Solve for x
    x = 661,210.04/858.87
  6. Step 6: Final answer
    x = 769.86

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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.