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Finding the Fourth Proportional to 811.38, 1,211.56 and 644.98

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Solution

The fourth proportional to 811.38, 1,211.56 and 644.98 is: 963.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.38 : 1,211.56 = 644.98 : x
  2. Step 2: Convert to fraction form
    811.38/1,211.56 = 644.98/x
  3. Step 3: Cross multiply
    811.38x = 1,211.56 × 644.98
  4. Step 4: Simplify right side
    811.38x = 781,429.60
  5. Step 5: Solve for x
    x = 781,429.60/811.38
  6. Step 6: Final answer
    x = 963.08

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.