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Finding the Fourth Proportional to 145.56, 218.40 and 128.40

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Solution

The fourth proportional to 145.56, 218.40 and 128.40 is: 192.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.56 : 218.40 = 128.40 : x
  2. Step 2: Convert to fraction form
    145.56/218.40 = 128.40/x
  3. Step 3: Cross multiply
    145.56x = 218.40 × 128.40
  4. Step 4: Simplify right side
    145.56x = 28,042.56
  5. Step 5: Solve for x
    x = 28,042.56/145.56
  6. Step 6: Final answer
    x = 192.65

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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.