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Finding the Fourth Proportional to 93.50, 128.90 and 65.79

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Solution

The fourth proportional to 93.50, 128.90 and 65.79 is: 90.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.50 : 128.90 = 65.79 : x
  2. Step 2: Convert to fraction form
    93.50/128.90 = 65.79/x
  3. Step 3: Cross multiply
    93.50x = 128.90 × 65.79
  4. Step 4: Simplify right side
    93.50x = 8,480.01
  5. Step 5: Solve for x
    x = 8,480.01/93.50
  6. Step 6: Final answer
    x = 90.69

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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.