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Finding the Fourth Proportional to 838.12, 1,257.43 and 399.70

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Solution

The fourth proportional to 838.12, 1,257.43 and 399.70 is: 599.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.12 : 1,257.43 = 399.70 : x
  2. Step 2: Convert to fraction form
    838.12/1,257.43 = 399.70/x
  3. Step 3: Cross multiply
    838.12x = 1,257.43 × 399.70
  4. Step 4: Simplify right side
    838.12x = 502,594.77
  5. Step 5: Solve for x
    x = 502,594.77/838.12
  6. Step 6: Final answer
    x = 599.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.