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Finding the Fourth Proportional to 386.65, 580.78 and 338.05

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Solution

The fourth proportional to 386.65, 580.78 and 338.05 is: 507.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.65 : 580.78 = 338.05 : x
  2. Step 2: Convert to fraction form
    386.65/580.78 = 338.05/x
  3. Step 3: Cross multiply
    386.65x = 580.78 × 338.05
  4. Step 4: Simplify right side
    386.65x = 196,329.78
  5. Step 5: Solve for x
    x = 196,329.78/386.65
  6. Step 6: Final answer
    x = 507.78

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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.