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Finding the Fourth Proportional to 316.71, 438.75 and 309.15

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Solution

The fourth proportional to 316.71, 438.75 and 309.15 is: 428.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    316.71 : 438.75 = 309.15 : x
  2. Step 2: Convert to fraction form
    316.71/438.75 = 309.15/x
  3. Step 3: Cross multiply
    316.71x = 438.75 × 309.15
  4. Step 4: Simplify right side
    316.71x = 135,639.56
  5. Step 5: Solve for x
    x = 135,639.56/316.71
  6. Step 6: Final answer
    x = 428.28

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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.