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Finding the Fourth Proportional to 90.02, 123.91 and 79.70

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Solution

The fourth proportional to 90.02, 123.91 and 79.70 is: 109.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.02 : 123.91 = 79.70 : x
  2. Step 2: Convert to fraction form
    90.02/123.91 = 79.70/x
  3. Step 3: Cross multiply
    90.02x = 123.91 × 79.70
  4. Step 4: Simplify right side
    90.02x = 9,876.04
  5. Step 5: Solve for x
    x = 9,876.04/90.02
  6. Step 6: Final answer
    x = 109.70

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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.