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Finding the Fourth Proportional to 1,428.68, 1,971.06 and 838.78

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Solution

The fourth proportional to 1,428.68, 1,971.06 and 838.78 is: 1,157.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.68 : 1,971.06 = 838.78 : x
  2. Step 2: Convert to fraction form
    1,428.68/1,971.06 = 838.78/x
  3. Step 3: Cross multiply
    1,428.68x = 1,971.06 × 838.78
  4. Step 4: Simplify right side
    1,428.68x = 1,653,285.71
  5. Step 5: Solve for x
    x = 1,653,285.71/1,428.68
  6. Step 6: Final answer
    x = 1,157.21

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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.