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Finding the Fourth Proportional to 977.36, 1,348.82 and 645.21

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Solution

The fourth proportional to 977.36, 1,348.82 and 645.21 is: 890.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    977.36 : 1,348.82 = 645.21 : x
  2. Step 2: Convert to fraction form
    977.36/1,348.82 = 645.21/x
  3. Step 3: Cross multiply
    977.36x = 1,348.82 × 645.21
  4. Step 4: Simplify right side
    977.36x = 870,272.15
  5. Step 5: Solve for x
    x = 870,272.15/977.36
  6. Step 6: Final answer
    x = 890.43

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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.