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Finding the Fourth Proportional to 786.29, 1,179.40 and 421.79

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Solution

The fourth proportional to 786.29, 1,179.40 and 421.79 is: 632.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.29 : 1,179.40 = 421.79 : x
  2. Step 2: Convert to fraction form
    786.29/1,179.40 = 421.79/x
  3. Step 3: Cross multiply
    786.29x = 1,179.40 × 421.79
  4. Step 4: Simplify right side
    786.29x = 497,451.12
  5. Step 5: Solve for x
    x = 497,451.12/786.29
  6. Step 6: Final answer
    x = 632.66

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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.