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Finding the Fourth Proportional to 88.40, 121.74 and 71.90

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Solution

The fourth proportional to 88.40, 121.74 and 71.90 is: 99.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.40 : 121.74 = 71.90 : x
  2. Step 2: Convert to fraction form
    88.40/121.74 = 71.90/x
  3. Step 3: Cross multiply
    88.40x = 121.74 × 71.90
  4. Step 4: Simplify right side
    88.40x = 8,753.11
  5. Step 5: Solve for x
    x = 8,753.11/88.40
  6. Step 6: Final answer
    x = 99.02

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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.