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Finding the Fourth Proportional to 786.70, 1,180.28 and 421.21

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Solution

The fourth proportional to 786.70, 1,180.28 and 421.21 is: 631.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.70 : 1,180.28 = 421.21 : x
  2. Step 2: Convert to fraction form
    786.70/1,180.28 = 421.21/x
  3. Step 3: Cross multiply
    786.70x = 1,180.28 × 421.21
  4. Step 4: Simplify right side
    786.70x = 497,145.74
  5. Step 5: Solve for x
    x = 497,145.74/786.70
  6. Step 6: Final answer
    x = 631.94

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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.