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Finding the Fourth Proportional to 93.21, 128.66 and 56.40

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Solution

The fourth proportional to 93.21, 128.66 and 56.40 is: 77.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.21 : 128.66 = 56.40 : x
  2. Step 2: Convert to fraction form
    93.21/128.66 = 56.40/x
  3. Step 3: Cross multiply
    93.21x = 128.66 × 56.40
  4. Step 4: Simplify right side
    93.21x = 7,256.14
  5. Step 5: Solve for x
    x = 7,256.14/93.21
  6. Step 6: Final answer
    x = 77.85

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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.