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Finding the Fourth Proportional to 838.72, 1,258.24 and 428.08

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Solution

The fourth proportional to 838.72, 1,258.24 and 428.08 is: 642.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.72 : 1,258.24 = 428.08 : x
  2. Step 2: Convert to fraction form
    838.72/1,258.24 = 428.08/x
  3. Step 3: Cross multiply
    838.72x = 1,258.24 × 428.08
  4. Step 4: Simplify right side
    838.72x = 538,627.38
  5. Step 5: Solve for x
    x = 538,627.38/838.72
  6. Step 6: Final answer
    x = 642.20

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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.