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Finding the Fourth Proportional to 645.77, 890.12 and 505.66

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Solution

The fourth proportional to 645.77, 890.12 and 505.66 is: 696.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.77 : 890.12 = 505.66 : x
  2. Step 2: Convert to fraction form
    645.77/890.12 = 505.66/x
  3. Step 3: Cross multiply
    645.77x = 890.12 × 505.66
  4. Step 4: Simplify right side
    645.77x = 450,091.10
  5. Step 5: Solve for x
    x = 450,091.10/645.77
  6. Step 6: Final answer
    x = 696.99

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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.