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Finding the Fourth Proportional to 89.51, 123.56 and 56.78

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Solution

The fourth proportional to 89.51, 123.56 and 56.78 is: 78.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.51 : 123.56 = 56.78 : x
  2. Step 2: Convert to fraction form
    89.51/123.56 = 56.78/x
  3. Step 3: Cross multiply
    89.51x = 123.56 × 56.78
  4. Step 4: Simplify right side
    89.51x = 7,014.84
  5. Step 5: Solve for x
    x = 7,014.84/89.51
  6. Step 6: Final answer
    x = 78.37

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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.