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Finding the Fourth Proportional to 85.28, 117.72 and 56.16

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Solution

The fourth proportional to 85.28, 117.72 and 56.16 is: 77.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 117.72 = 56.16 : x
  2. Step 2: Convert to fraction form
    85.28/117.72 = 56.16/x
  3. Step 3: Cross multiply
    85.28x = 117.72 × 56.16
  4. Step 4: Simplify right side
    85.28x = 6,611.16
  5. Step 5: Solve for x
    x = 6,611.16/85.28
  6. Step 6: Final answer
    x = 77.52

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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.