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Finding the Fourth Proportional to 857.09, 1,180.73 and 815.40

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Solution

The fourth proportional to 857.09, 1,180.73 and 815.40 is: 1,123.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.09 : 1,180.73 = 815.40 : x
  2. Step 2: Convert to fraction form
    857.09/1,180.73 = 815.40/x
  3. Step 3: Cross multiply
    857.09x = 1,180.73 × 815.40
  4. Step 4: Simplify right side
    857.09x = 962,763.17
  5. Step 5: Solve for x
    x = 962,763.17/857.09
  6. Step 6: Final answer
    x = 1,123.30

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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.