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Finding the Fourth Proportional to 202.40, 279.36 and 128.80

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Solution

The fourth proportional to 202.40, 279.36 and 128.80 is: 177.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    202.40 : 279.36 = 128.80 : x
  2. Step 2: Convert to fraction form
    202.40/279.36 = 128.80/x
  3. Step 3: Cross multiply
    202.40x = 279.36 × 128.80
  4. Step 4: Simplify right side
    202.40x = 35,981.57
  5. Step 5: Solve for x
    x = 35,981.57/202.40
  6. Step 6: Final answer
    x = 177.77

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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.