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Finding the Fourth Proportional to 87.69, 121.13 and 80

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Solution

The fourth proportional to 87.69, 121.13 and 80 is: 110.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.69 : 121.13 = 80 : x
  2. Step 2: Convert to fraction form
    87.69/121.13 = 80/x
  3. Step 3: Cross multiply
    87.69x = 121.13 × 80
  4. Step 4: Simplify right side
    87.69x = 9,690.40
  5. Step 5: Solve for x
    x = 9,690.40/87.69
  6. Step 6: Final answer
    x = 110.51

Related Problems

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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.