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Finding the Fourth Proportional to 142.65, 213.89 and 91.40

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Solution

The fourth proportional to 142.65, 213.89 and 91.40 is: 137.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.65 : 213.89 = 91.40 : x
  2. Step 2: Convert to fraction form
    142.65/213.89 = 91.40/x
  3. Step 3: Cross multiply
    142.65x = 213.89 × 91.40
  4. Step 4: Simplify right side
    142.65x = 19,548.02
  5. Step 5: Solve for x
    x = 19,548.02/142.65
  6. Step 6: Final answer
    x = 137.03

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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.