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Finding the Fourth Proportional to 7.80, 10.66 and 7.74

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Solution

The fourth proportional to 7.80, 10.66 and 7.74 is: 10.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.80 : 10.66 = 7.74 : x
  2. Step 2: Convert to fraction form
    7.80/10.66 = 7.74/x
  3. Step 3: Cross multiply
    7.80x = 10.66 × 7.74
  4. Step 4: Simplify right side
    7.80x = 82.51
  5. Step 5: Solve for x
    x = 82.51/7.80
  6. Step 6: Final answer
    x = 10.58

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.