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Finding the Fourth Proportional to 90, 123.92 and 80.76

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Solution

The fourth proportional to 90, 123.92 and 80.76 is: 111.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    90 : 123.92 = 80.76 : x
  2. Step 2: Convert to fraction form
    90/123.92 = 80.76/x
  3. Step 3: Cross multiply
    90x = 123.92 × 80.76
  4. Step 4: Simplify right side
    90x = 10,007.78
  5. Step 5: Solve for x
    x = 10,007.78/90
  6. Step 6: Final answer
    x = 111.20

Related Problems

Find fourth proportional to 45, 61.96 and 40.38
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1.5x scale

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.