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Finding the Fourth Proportional to 858.72, 1,287.76 and 338.36

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Solution

The fourth proportional to 858.72, 1,287.76 and 338.36 is: 507.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.72 : 1,287.76 = 338.36 : x
  2. Step 2: Convert to fraction form
    858.72/1,287.76 = 338.36/x
  3. Step 3: Cross multiply
    858.72x = 1,287.76 × 338.36
  4. Step 4: Simplify right side
    858.72x = 435,726.47
  5. Step 5: Solve for x
    x = 435,726.47/858.72
  6. Step 6: Final answer
    x = 507.41

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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.