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Finding the Fourth Proportional to 143.28, 215 and 71.20

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Solution

The fourth proportional to 143.28, 215 and 71.20 is: 106.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.28 : 215 = 71.20 : x
  2. Step 2: Convert to fraction form
    143.28/215 = 71.20/x
  3. Step 3: Cross multiply
    143.28x = 215 × 71.20
  4. Step 4: Simplify right side
    143.28x = 15,308
  5. Step 5: Solve for x
    x = 15,308/143.28
  6. Step 6: Final answer
    x = 106.84

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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.