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Finding the Fourth Proportional to 1,428.10, 1,970.91 and 838.61

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Solution

The fourth proportional to 1,428.10, 1,970.91 and 838.61 is: 1,157.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.10 : 1,970.91 = 838.61 : x
  2. Step 2: Convert to fraction form
    1,428.10/1,970.91 = 838.61/x
  3. Step 3: Cross multiply
    1,428.10x = 1,970.91 × 838.61
  4. Step 4: Simplify right side
    1,428.10x = 1,652,824.84
  5. Step 5: Solve for x
    x = 1,652,824.84/1,428.10
  6. Step 6: Final answer
    x = 1,157.36

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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.