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Finding the Fourth Proportional to 64.56, 89.30 and 56.90

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Solution

The fourth proportional to 64.56, 89.30 and 56.90 is: 78.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.56 : 89.30 = 56.90 : x
  2. Step 2: Convert to fraction form
    64.56/89.30 = 56.90/x
  3. Step 3: Cross multiply
    64.56x = 89.30 × 56.90
  4. Step 4: Simplify right side
    64.56x = 5,081.17
  5. Step 5: Solve for x
    x = 5,081.17/64.56
  6. Step 6: Final answer
    x = 78.70

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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.