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Finding the Fourth Proportional to 85.59, 128.52 and 56.70

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Solution

The fourth proportional to 85.59, 128.52 and 56.70 is: 85.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.59 : 128.52 = 56.70 : x
  2. Step 2: Convert to fraction form
    85.59/128.52 = 56.70/x
  3. Step 3: Cross multiply
    85.59x = 128.52 × 56.70
  4. Step 4: Simplify right side
    85.59x = 7,287.08
  5. Step 5: Solve for x
    x = 7,287.08/85.59
  6. Step 6: Final answer
    x = 85.14

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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.