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Finding the Fourth Proportional to 128.00, 176.51 and 91.15

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Solution

The fourth proportional to 128.00, 176.51 and 91.15 is: 125.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.00 : 176.51 = 91.15 : x
  2. Step 2: Convert to fraction form
    128.00/176.51 = 91.15/x
  3. Step 3: Cross multiply
    128.00x = 176.51 × 91.15
  4. Step 4: Simplify right side
    128.00x = 16,088.67
  5. Step 5: Solve for x
    x = 16,088.67/128.00
  6. Step 6: Final answer
    x = 125.69

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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.