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Finding the Fourth Proportional to 1,398.60, 1,929.78 and 838.92

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Solution

The fourth proportional to 1,398.60, 1,929.78 and 838.92 is: 1,157.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,398.60 : 1,929.78 = 838.92 : x
  2. Step 2: Convert to fraction form
    1,398.60/1,929.78 = 838.92/x
  3. Step 3: Cross multiply
    1,398.60x = 1,929.78 × 838.92
  4. Step 4: Simplify right side
    1,398.60x = 1,618,931.04
  5. Step 5: Solve for x
    x = 1,618,931.04/1,398.60
  6. Step 6: Final answer
    x = 1,157.54

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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.