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Finding the Fourth Proportional to 100.59, 138.79 and 56.91

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Solution

The fourth proportional to 100.59, 138.79 and 56.91 is: 78.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.59 : 138.79 = 56.91 : x
  2. Step 2: Convert to fraction form
    100.59/138.79 = 56.91/x
  3. Step 3: Cross multiply
    100.59x = 138.79 × 56.91
  4. Step 4: Simplify right side
    100.59x = 7,899.13
  5. Step 5: Solve for x
    x = 7,899.13/100.59
  6. Step 6: Final answer
    x = 78.53

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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.