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Finding the Fourth Proportional to 88, 121.40 and 76.40

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Solution

The fourth proportional to 88, 121.40 and 76.40 is: 105.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    88 : 121.40 = 76.40 : x
  2. Step 2: Convert to fraction form
    88/121.40 = 76.40/x
  3. Step 3: Cross multiply
    88x = 121.40 × 76.40
  4. Step 4: Simplify right side
    88x = 9,274.96
  5. Step 5: Solve for x
    x = 9,274.96/88
  6. Step 6: Final answer
    x = 105.40

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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.