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Finding the Fourth Proportional to 578.40, 811.20 and 578.40

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Solution

The fourth proportional to 578.40, 811.20 and 578.40 is: 811.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    578.40 : 811.20 = 578.40 : x
  2. Step 2: Convert to fraction form
    578.40/811.20 = 578.40/x
  3. Step 3: Cross multiply
    578.40x = 811.20 × 578.40
  4. Step 4: Simplify right side
    578.40x = 469,198.08
  5. Step 5: Solve for x
    x = 469,198.08/578.40
  6. Step 6: Final answer
    x = 811.20

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Half scale
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.