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Finding the Fourth Proportional to 128.77, 177.54 and 89.89

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Solution

The fourth proportional to 128.77, 177.54 and 89.89 is: 123.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.77 : 177.54 = 89.89 : x
  2. Step 2: Convert to fraction form
    128.77/177.54 = 89.89/x
  3. Step 3: Cross multiply
    128.77x = 177.54 × 89.89
  4. Step 4: Simplify right side
    128.77x = 15,959.07
  5. Step 5: Solve for x
    x = 15,959.07/128.77
  6. Step 6: Final answer
    x = 123.93

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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.