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Finding the Fourth Proportional to 84.90, 117.22 and 64.20

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Solution

The fourth proportional to 84.90, 117.22 and 64.20 is: 88.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.90 : 117.22 = 64.20 : x
  2. Step 2: Convert to fraction form
    84.90/117.22 = 64.20/x
  3. Step 3: Cross multiply
    84.90x = 117.22 × 64.20
  4. Step 4: Simplify right side
    84.90x = 7,525.52
  5. Step 5: Solve for x
    x = 7,525.52/84.90
  6. Step 6: Final answer
    x = 88.64

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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.