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Finding the Fourth Proportional to 811.49, 1,216.62 and 420.96

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Solution

The fourth proportional to 811.49, 1,216.62 and 420.96 is: 631.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.49 : 1,216.62 = 420.96 : x
  2. Step 2: Convert to fraction form
    811.49/1,216.62 = 420.96/x
  3. Step 3: Cross multiply
    811.49x = 1,216.62 × 420.96
  4. Step 4: Simplify right side
    811.49x = 512,152.92
  5. Step 5: Solve for x
    x = 512,152.92/811.49
  6. Step 6: Final answer
    x = 631.13

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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.