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Finding the Fourth Proportional to 91.38, 126 and 85.80

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Solution

The fourth proportional to 91.38, 126 and 85.80 is: 118.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.38 : 126 = 85.80 : x
  2. Step 2: Convert to fraction form
    91.38/126 = 85.80/x
  3. Step 3: Cross multiply
    91.38x = 126 × 85.80
  4. Step 4: Simplify right side
    91.38x = 10,810.80
  5. Step 5: Solve for x
    x = 10,810.80/91.38
  6. Step 6: Final answer
    x = 118.31

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1.5x scale

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.