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Finding the Fourth Proportional to 12.80, 17.65 and 12.40

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Solution

The fourth proportional to 12.80, 17.65 and 12.40 is: 17.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.80 : 17.65 = 12.40 : x
  2. Step 2: Convert to fraction form
    12.80/17.65 = 12.40/x
  3. Step 3: Cross multiply
    12.80x = 17.65 × 12.40
  4. Step 4: Simplify right side
    12.80x = 218.81
  5. Step 5: Solve for x
    x = 218.81/12.80
  6. Step 6: Final answer
    x = 17.10

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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.