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Finding the Fourth Proportional to 42.86, 64.32 and 17.20

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Solution

The fourth proportional to 42.86, 64.32 and 17.20 is: 25.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.86 : 64.32 = 17.20 : x
  2. Step 2: Convert to fraction form
    42.86/64.32 = 17.20/x
  3. Step 3: Cross multiply
    42.86x = 64.32 × 17.20
  4. Step 4: Simplify right side
    42.86x = 1,106.30
  5. Step 5: Solve for x
    x = 1,106.30/42.86
  6. Step 6: Final answer
    x = 25.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.