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Finding the Fourth Proportional to 320.72, 440.02 and 312.56

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Solution

The fourth proportional to 320.72, 440.02 and 312.56 is: 428.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.72 : 440.02 = 312.56 : x
  2. Step 2: Convert to fraction form
    320.72/440.02 = 312.56/x
  3. Step 3: Cross multiply
    320.72x = 440.02 × 312.56
  4. Step 4: Simplify right side
    320.72x = 137,532.65
  5. Step 5: Solve for x
    x = 137,532.65/320.72
  6. Step 6: Final answer
    x = 428.82

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.