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Finding the Fourth Proportional to 518.65, 778.11 and 431.51

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Solution

The fourth proportional to 518.65, 778.11 and 431.51 is: 647.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.65 : 778.11 = 431.51 : x
  2. Step 2: Convert to fraction form
    518.65/778.11 = 431.51/x
  3. Step 3: Cross multiply
    518.65x = 778.11 × 431.51
  4. Step 4: Simplify right side
    518.65x = 335,762.25
  5. Step 5: Solve for x
    x = 335,762.25/518.65
  6. Step 6: Final answer
    x = 647.38

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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.