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Finding the Fourth Proportional to 786.16, 1,179.21 and 421.66

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Solution

The fourth proportional to 786.16, 1,179.21 and 421.66 is: 632.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.16 : 1,179.21 = 421.66 : x
  2. Step 2: Convert to fraction form
    786.16/1,179.21 = 421.66/x
  3. Step 3: Cross multiply
    786.16x = 1,179.21 × 421.66
  4. Step 4: Simplify right side
    786.16x = 497,222.74
  5. Step 5: Solve for x
    x = 497,222.74/786.16
  6. Step 6: Final answer
    x = 632.47

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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.