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Finding the Fourth Proportional to 811.46, 1,217.20 and 378.32

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Solution

The fourth proportional to 811.46, 1,217.20 and 378.32 is: 567.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.46 : 1,217.20 = 378.32 : x
  2. Step 2: Convert to fraction form
    811.46/1,217.20 = 378.32/x
  3. Step 3: Cross multiply
    811.46x = 1,217.20 × 378.32
  4. Step 4: Simplify right side
    811.46x = 460,491.10
  5. Step 5: Solve for x
    x = 460,491.10/811.46
  6. Step 6: Final answer
    x = 567.48

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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.