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Finding the Fourth Proportional to 858.56, 1,287.90 and 338.58

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Solution

The fourth proportional to 858.56, 1,287.90 and 338.58 is: 507.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.56 : 1,287.90 = 338.58 : x
  2. Step 2: Convert to fraction form
    858.56/1,287.90 = 338.58/x
  3. Step 3: Cross multiply
    858.56x = 1,287.90 × 338.58
  4. Step 4: Simplify right side
    858.56x = 436,057.18
  5. Step 5: Solve for x
    x = 436,057.18/858.56
  6. Step 6: Final answer
    x = 507.90

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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.