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Finding the Fourth Proportional to 7.80, 10.72 and 7

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Solution

The fourth proportional to 7.80, 10.72 and 7 is: 9.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.80 : 10.72 = 7 : x
  2. Step 2: Convert to fraction form
    7.80/10.72 = 7/x
  3. Step 3: Cross multiply
    7.80x = 10.72 × 7
  4. Step 4: Simplify right side
    7.80x = 75.04
  5. Step 5: Solve for x
    x = 75.04/7.80
  6. Step 6: Final answer
    x = 9.62

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