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Finding the Fourth Proportional to 660.20, 913.38 and 645.80

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Solution

The fourth proportional to 660.20, 913.38 and 645.80 is: 893.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.20 : 913.38 = 645.80 : x
  2. Step 2: Convert to fraction form
    660.20/913.38 = 645.80/x
  3. Step 3: Cross multiply
    660.20x = 913.38 × 645.80
  4. Step 4: Simplify right side
    660.20x = 589,860.80
  5. Step 5: Solve for x
    x = 589,860.80/660.20
  6. Step 6: Final answer
    x = 893.46

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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.