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Finding the Fourth Proportional to 890.40, 1,226.85 and 640.92

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Solution

The fourth proportional to 890.40, 1,226.85 and 640.92 is: 883.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.40 : 1,226.85 = 640.92 : x
  2. Step 2: Convert to fraction form
    890.40/1,226.85 = 640.92/x
  3. Step 3: Cross multiply
    890.40x = 1,226.85 × 640.92
  4. Step 4: Simplify right side
    890.40x = 786,312.70
  5. Step 5: Solve for x
    x = 786,312.70/890.40
  6. Step 6: Final answer
    x = 883.10

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1.5x scale

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.