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Finding the Fourth Proportional to 9, 12.38 and 7.79

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Solution

The fourth proportional to 9, 12.38 and 7.79 is: 10.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    9 : 12.38 = 7.79 : x
  2. Step 2: Convert to fraction form
    9/12.38 = 7.79/x
  3. Step 3: Cross multiply
    9x = 12.38 × 7.79
  4. Step 4: Simplify right side
    9x = 96.34
  5. Step 5: Solve for x
    x = 96.34/9
  6. Step 6: Final answer
    x = 10.70

Related Problems

Find fourth proportional to 4.50, 6.19 and 3.89
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1.5x scale

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.