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Finding the Fourth Proportional to 66.64, 99.78 and 56.28

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Solution

The fourth proportional to 66.64, 99.78 and 56.28 is: 84.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.64 : 99.78 = 56.28 : x
  2. Step 2: Convert to fraction form
    66.64/99.78 = 56.28/x
  3. Step 3: Cross multiply
    66.64x = 99.78 × 56.28
  4. Step 4: Simplify right side
    66.64x = 5,615.62
  5. Step 5: Solve for x
    x = 5,615.62/66.64
  6. Step 6: Final answer
    x = 84.27

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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.