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Finding the Fourth Proportional to 85.46, 128.01 and 70.19

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Solution

The fourth proportional to 85.46, 128.01 and 70.19 is: 105.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.46 : 128.01 = 70.19 : x
  2. Step 2: Convert to fraction form
    85.46/128.01 = 70.19/x
  3. Step 3: Cross multiply
    85.46x = 128.01 × 70.19
  4. Step 4: Simplify right side
    85.46x = 8,985.02
  5. Step 5: Solve for x
    x = 8,985.02/85.46
  6. Step 6: Final answer
    x = 105.14

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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.