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Finding the Fourth Proportional to 145.50, 218.30 and 81.42

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Solution

The fourth proportional to 145.50, 218.30 and 81.42 is: 122.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.50 : 218.30 = 81.42 : x
  2. Step 2: Convert to fraction form
    145.50/218.30 = 81.42/x
  3. Step 3: Cross multiply
    145.50x = 218.30 × 81.42
  4. Step 4: Simplify right side
    145.50x = 17,773.99
  5. Step 5: Solve for x
    x = 17,773.99/145.50
  6. Step 6: Final answer
    x = 122.16

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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.