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Finding the Fourth Proportional to 315.78, 439.26 and 309.84

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Solution

The fourth proportional to 315.78, 439.26 and 309.84 is: 431.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    315.78 : 439.26 = 309.84 : x
  2. Step 2: Convert to fraction form
    315.78/439.26 = 309.84/x
  3. Step 3: Cross multiply
    315.78x = 439.26 × 309.84
  4. Step 4: Simplify right side
    315.78x = 136,100.32
  5. Step 5: Solve for x
    x = 136,100.32/315.78
  6. Step 6: Final answer
    x = 431.00

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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.