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Finding the Fourth Proportional to 64.80, 87.75 and 64.80

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Solution

The fourth proportional to 64.80, 87.75 and 64.80 is: 87.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.80 : 87.75 = 64.80 : x
  2. Step 2: Convert to fraction form
    64.80/87.75 = 64.80/x
  3. Step 3: Cross multiply
    64.80x = 87.75 × 64.80
  4. Step 4: Simplify right side
    64.80x = 5,686.20
  5. Step 5: Solve for x
    x = 5,686.20/64.80
  6. Step 6: Final answer
    x = 87.75

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.