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Finding the Fourth Proportional to 786.16, 1,179.77 and 421.21

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Solution

The fourth proportional to 786.16, 1,179.77 and 421.21 is: 632.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.16 : 1,179.77 = 421.21 : x
  2. Step 2: Convert to fraction form
    786.16/1,179.77 = 421.21/x
  3. Step 3: Cross multiply
    786.16x = 1,179.77 × 421.21
  4. Step 4: Simplify right side
    786.16x = 496,930.92
  5. Step 5: Solve for x
    x = 496,930.92/786.16
  6. Step 6: Final answer
    x = 632.10

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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.