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Finding the Fourth Proportional to 860.10, 1,288.80 and 641.40

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Solution

The fourth proportional to 860.10, 1,288.80 and 641.40 is: 961.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.10 : 1,288.80 = 641.40 : x
  2. Step 2: Convert to fraction form
    860.10/1,288.80 = 641.40/x
  3. Step 3: Cross multiply
    860.10x = 1,288.80 × 641.40
  4. Step 4: Simplify right side
    860.10x = 826,636.32
  5. Step 5: Solve for x
    x = 826,636.32/860.10
  6. Step 6: Final answer
    x = 961.09

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1.5x scale

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.