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Finding the Fourth Proportional to 66.49, 99.78 and 56.64

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Solution

The fourth proportional to 66.49, 99.78 and 56.64 is: 85.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.49 : 99.78 = 56.64 : x
  2. Step 2: Convert to fraction form
    66.49/99.78 = 56.64/x
  3. Step 3: Cross multiply
    66.49x = 99.78 × 56.64
  4. Step 4: Simplify right side
    66.49x = 5,651.54
  5. Step 5: Solve for x
    x = 5,651.54/66.49
  6. Step 6: Final answer
    x = 85.00

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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.