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Finding the Fourth Proportional to 87.95, 121.40 and 64.63

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Solution

The fourth proportional to 87.95, 121.40 and 64.63 is: 89.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.95 : 121.40 = 64.63 : x
  2. Step 2: Convert to fraction form
    87.95/121.40 = 64.63/x
  3. Step 3: Cross multiply
    87.95x = 121.40 × 64.63
  4. Step 4: Simplify right side
    87.95x = 7,846.08
  5. Step 5: Solve for x
    x = 7,846.08/87.95
  6. Step 6: Final answer
    x = 89.21

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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.