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Finding the Fourth Proportional to 974.12, 1,340.78 and 815.00

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Solution

The fourth proportional to 974.12, 1,340.78 and 815.00 is: 1,121.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    974.12 : 1,340.78 = 815.00 : x
  2. Step 2: Convert to fraction form
    974.12/1,340.78 = 815.00/x
  3. Step 3: Cross multiply
    974.12x = 1,340.78 × 815.00
  4. Step 4: Simplify right side
    974.12x = 1,092,734.98
  5. Step 5: Solve for x
    x = 1,092,734.98/974.12
  6. Step 6: Final answer
    x = 1,121.77

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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.