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Finding the Fourth Proportional to 317.21, 439.45 and 309.65

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Solution

The fourth proportional to 317.21, 439.45 and 309.65 is: 428.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    317.21 : 439.45 = 309.65 : x
  2. Step 2: Convert to fraction form
    317.21/439.45 = 309.65/x
  3. Step 3: Cross multiply
    317.21x = 439.45 × 309.65
  4. Step 4: Simplify right side
    317.21x = 136,074.14
  5. Step 5: Solve for x
    x = 136,074.14/317.21
  6. Step 6: Final answer
    x = 428.97

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.