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Finding the Fourth Proportional to 91.15, 125.80 and 64.91

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Solution

The fourth proportional to 91.15, 125.80 and 64.91 is: 89.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.15 : 125.80 = 64.91 : x
  2. Step 2: Convert to fraction form
    91.15/125.80 = 64.91/x
  3. Step 3: Cross multiply
    91.15x = 125.80 × 64.91
  4. Step 4: Simplify right side
    91.15x = 8,165.83
  5. Step 5: Solve for x
    x = 8,165.83/91.15
  6. Step 6: Final answer
    x = 89.59

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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.