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Finding the Fourth Proportional to 830.36, 1,238.08 and 815.78

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Solution

The fourth proportional to 830.36, 1,238.08 and 815.78 is: 1,216.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.36 : 1,238.08 = 815.78 : x
  2. Step 2: Convert to fraction form
    830.36/1,238.08 = 815.78/x
  3. Step 3: Cross multiply
    830.36x = 1,238.08 × 815.78
  4. Step 4: Simplify right side
    830.36x = 1,010,000.90
  5. Step 5: Solve for x
    x = 1,010,000.90/830.36
  6. Step 6: Final answer
    x = 1,216.34

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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.