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Finding the Fourth Proportional to 977.11, 1,348.36 and 645.42

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Solution

The fourth proportional to 977.11, 1,348.36 and 645.42 is: 890.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    977.11 : 1,348.36 = 645.42 : x
  2. Step 2: Convert to fraction form
    977.11/1,348.36 = 645.42/x
  3. Step 3: Cross multiply
    977.11x = 1,348.36 × 645.42
  4. Step 4: Simplify right side
    977.11x = 870,258.51
  5. Step 5: Solve for x
    x = 870,258.51/977.11
  6. Step 6: Final answer
    x = 890.65

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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.