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Finding the Fourth Proportional to 67.80, 102.16 and 56.64

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Solution

The fourth proportional to 67.80, 102.16 and 56.64 is: 85.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.80 : 102.16 = 56.64 : x
  2. Step 2: Convert to fraction form
    67.80/102.16 = 56.64/x
  3. Step 3: Cross multiply
    67.80x = 102.16 × 56.64
  4. Step 4: Simplify right side
    67.80x = 5,786.34
  5. Step 5: Solve for x
    x = 5,786.34/67.80
  6. Step 6: Final answer
    x = 85.34

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.