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Finding the Fourth Proportional to 65.80, 90.90 and 56.20

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Solution

The fourth proportional to 65.80, 90.90 and 56.20 is: 77.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.80 : 90.90 = 56.20 : x
  2. Step 2: Convert to fraction form
    65.80/90.90 = 56.20/x
  3. Step 3: Cross multiply
    65.80x = 90.90 × 56.20
  4. Step 4: Simplify right side
    65.80x = 5,108.58
  5. Step 5: Solve for x
    x = 5,108.58/65.80
  6. Step 6: Final answer
    x = 77.64

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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.