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Finding the Fourth Proportional to 71.65, 106.91 and 70.21

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Solution

The fourth proportional to 71.65, 106.91 and 70.21 is: 104.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.65 : 106.91 = 70.21 : x
  2. Step 2: Convert to fraction form
    71.65/106.91 = 70.21/x
  3. Step 3: Cross multiply
    71.65x = 106.91 × 70.21
  4. Step 4: Simplify right side
    71.65x = 7,506.15
  5. Step 5: Solve for x
    x = 7,506.15/71.65
  6. Step 6: Final answer
    x = 104.76

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.