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Finding the Fourth Proportional to 88.30, 121.90 and 66.50

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Solution

The fourth proportional to 88.30, 121.90 and 66.50 is: 91.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.30 : 121.90 = 66.50 : x
  2. Step 2: Convert to fraction form
    88.30/121.90 = 66.50/x
  3. Step 3: Cross multiply
    88.30x = 121.90 × 66.50
  4. Step 4: Simplify right side
    88.30x = 8,105.57
  5. Step 5: Solve for x
    x = 8,105.57/88.30
  6. Step 6: Final answer
    x = 91.80

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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.