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Finding the Fourth Proportional to 106.40, 159.46 and 77.21

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Solution

The fourth proportional to 106.40, 159.46 and 77.21 is: 115.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    106.40 : 159.46 = 77.21 : x
  2. Step 2: Convert to fraction form
    106.40/159.46 = 77.21/x
  3. Step 3: Cross multiply
    106.40x = 159.46 × 77.21
  4. Step 4: Simplify right side
    106.40x = 12,312.11
  5. Step 5: Solve for x
    x = 12,312.11/106.40
  6. Step 6: Final answer
    x = 115.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.