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Finding the Fourth Proportional to 142.68, 213.57 and 99.21

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Solution

The fourth proportional to 142.68, 213.57 and 99.21 is: 148.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.68 : 213.57 = 99.21 : x
  2. Step 2: Convert to fraction form
    142.68/213.57 = 99.21/x
  3. Step 3: Cross multiply
    142.68x = 213.57 × 99.21
  4. Step 4: Simplify right side
    142.68x = 21,188.28
  5. Step 5: Solve for x
    x = 21,188.28/142.68
  6. Step 6: Final answer
    x = 148.50

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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.