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Finding the Fourth Proportional to 487.45, 672.79 and 312.49

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Solution

The fourth proportional to 487.45, 672.79 and 312.49 is: 431.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.45 : 672.79 = 312.49 : x
  2. Step 2: Convert to fraction form
    487.45/672.79 = 312.49/x
  3. Step 3: Cross multiply
    487.45x = 672.79 × 312.49
  4. Step 4: Simplify right side
    487.45x = 210,236.78
  5. Step 5: Solve for x
    x = 210,236.78/487.45
  6. Step 6: Final answer
    x = 431.30

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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.