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Finding the Fourth Proportional to 1,405.49, 1,939.11 and 815.81

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Solution

The fourth proportional to 1,405.49, 1,939.11 and 815.81 is: 1,125.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,405.49 : 1,939.11 = 815.81 : x
  2. Step 2: Convert to fraction form
    1,405.49/1,939.11 = 815.81/x
  3. Step 3: Cross multiply
    1,405.49x = 1,939.11 × 815.81
  4. Step 4: Simplify right side
    1,405.49x = 1,581,935.63
  5. Step 5: Solve for x
    x = 1,581,935.63/1,405.49
  6. Step 6: Final answer
    x = 1,125.54

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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.