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Finding the Fourth Proportional to 513.55, 770.32 and 128.80

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Solution

The fourth proportional to 513.55, 770.32 and 128.80 is: 193.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    513.55 : 770.32 = 128.80 : x
  2. Step 2: Convert to fraction form
    513.55/770.32 = 128.80/x
  3. Step 3: Cross multiply
    513.55x = 770.32 × 128.80
  4. Step 4: Simplify right side
    513.55x = 99,213.36
  5. Step 5: Solve for x
    x = 99,213.36/513.55
  6. Step 6: Final answer
    x = 193.19

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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.