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Finding the Fourth Proportional to 312.84, 430.74 and 257.40

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Solution

The fourth proportional to 312.84, 430.74 and 257.40 is: 354.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.84 : 430.74 = 257.40 : x
  2. Step 2: Convert to fraction form
    312.84/430.74 = 257.40/x
  3. Step 3: Cross multiply
    312.84x = 430.74 × 257.40
  4. Step 4: Simplify right side
    312.84x = 110,872.48
  5. Step 5: Solve for x
    x = 110,872.48/312.84
  6. Step 6: Final answer
    x = 354.41

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.