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Finding the Fourth Proportional to 857.10, 1,285.65 and 641.10

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Solution

The fourth proportional to 857.10, 1,285.65 and 641.10 is: 961.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.10 : 1,285.65 = 641.10 : x
  2. Step 2: Convert to fraction form
    857.10/1,285.65 = 641.10/x
  3. Step 3: Cross multiply
    857.10x = 1,285.65 × 641.10
  4. Step 4: Simplify right side
    857.10x = 824,230.22
  5. Step 5: Solve for x
    x = 824,230.22/857.10
  6. Step 6: Final answer
    x = 961.65

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Double scale
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Similar ratio
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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.