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Finding the Fourth Proportional to 813.84, 1,221.12 and 429

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Solution

The fourth proportional to 813.84, 1,221.12 and 429 is: 643.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.84 : 1,221.12 = 429 : x
  2. Step 2: Convert to fraction form
    813.84/1,221.12 = 429/x
  3. Step 3: Cross multiply
    813.84x = 1,221.12 × 429
  4. Step 4: Simplify right side
    813.84x = 523,860.48
  5. Step 5: Solve for x
    x = 523,860.48/813.84
  6. Step 6: Final answer
    x = 643.69

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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.