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Finding the Fourth Proportional to 1,388.70, 1,916.10 and 799.20

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Solution

The fourth proportional to 1,388.70, 1,916.10 and 799.20 is: 1,102.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.70 : 1,916.10 = 799.20 : x
  2. Step 2: Convert to fraction form
    1,388.70/1,916.10 = 799.20/x
  3. Step 3: Cross multiply
    1,388.70x = 1,916.10 × 799.20
  4. Step 4: Simplify right side
    1,388.70x = 1,531,347.12
  5. Step 5: Solve for x
    x = 1,531,347.12/1,388.70
  6. Step 6: Final answer
    x = 1,102.72

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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.