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Finding the Fourth Proportional to 815.22, 1,215.69 and 783.72

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Solution

The fourth proportional to 815.22, 1,215.69 and 783.72 is: 1,168.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.22 : 1,215.69 = 783.72 : x
  2. Step 2: Convert to fraction form
    815.22/1,215.69 = 783.72/x
  3. Step 3: Cross multiply
    815.22x = 1,215.69 × 783.72
  4. Step 4: Simplify right side
    815.22x = 952,760.57
  5. Step 5: Solve for x
    x = 952,760.57/815.22
  6. Step 6: Final answer
    x = 1,168.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.