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Finding the Fourth Proportional to 786.12, 1,181.28 and 421.17

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Solution

The fourth proportional to 786.12, 1,181.28 and 421.17 is: 632.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.12 : 1,181.28 = 421.17 : x
  2. Step 2: Convert to fraction form
    786.12/1,181.28 = 421.17/x
  3. Step 3: Cross multiply
    786.12x = 1,181.28 × 421.17
  4. Step 4: Simplify right side
    786.12x = 497,519.70
  5. Step 5: Solve for x
    x = 497,519.70/786.12
  6. Step 6: Final answer
    x = 632.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.