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Finding the Fourth Proportional to 653.90, 980.90 and 645.90

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Solution

The fourth proportional to 653.90, 980.90 and 645.90 is: 968.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    653.90 : 980.90 = 645.90 : x
  2. Step 2: Convert to fraction form
    653.90/980.90 = 645.90/x
  3. Step 3: Cross multiply
    653.90x = 980.90 × 645.90
  4. Step 4: Simplify right side
    653.90x = 633,560.08
  5. Step 5: Solve for x
    x = 633,560.08/653.90
  6. Step 6: Final answer
    x = 968.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.