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Finding the Fourth Proportional to 190.47, 285.78 and 99.21

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Solution

The fourth proportional to 190.47, 285.78 and 99.21 is: 148.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    190.47 : 285.78 = 99.21 : x
  2. Step 2: Convert to fraction form
    190.47/285.78 = 99.21/x
  3. Step 3: Cross multiply
    190.47x = 285.78 × 99.21
  4. Step 4: Simplify right side
    190.47x = 28,352.23
  5. Step 5: Solve for x
    x = 28,352.23/190.47
  6. Step 6: Final answer
    x = 148.85

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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.