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Finding the Fourth Proportional to 838.70, 1,258.83 and 428.14

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Solution

The fourth proportional to 838.70, 1,258.83 and 428.14 is: 642.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.70 : 1,258.83 = 428.14 : x
  2. Step 2: Convert to fraction form
    838.70/1,258.83 = 428.14/x
  3. Step 3: Cross multiply
    838.70x = 1,258.83 × 428.14
  4. Step 4: Simplify right side
    838.70x = 538,953.34
  5. Step 5: Solve for x
    x = 538,953.34/838.70
  6. Step 6: Final answer
    x = 642.61

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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.