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Finding the Fourth Proportional to 145.40, 200.48 and 128.79

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Solution

The fourth proportional to 145.40, 200.48 and 128.79 is: 177.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.40 : 200.48 = 128.79 : x
  2. Step 2: Convert to fraction form
    145.40/200.48 = 128.79/x
  3. Step 3: Cross multiply
    145.40x = 200.48 × 128.79
  4. Step 4: Simplify right side
    145.40x = 25,819.18
  5. Step 5: Solve for x
    x = 25,819.18/145.40
  6. Step 6: Final answer
    x = 177.58

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.