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Finding the Fourth Proportional to 1,642.25, 2,461.55 and 821.21

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Solution

The fourth proportional to 1,642.25, 2,461.55 and 821.21 is: 1,230.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,642.25 : 2,461.55 = 821.21 : x
  2. Step 2: Convert to fraction form
    1,642.25/2,461.55 = 821.21/x
  3. Step 3: Cross multiply
    1,642.25x = 2,461.55 × 821.21
  4. Step 4: Simplify right side
    1,642.25x = 2,021,449.48
  5. Step 5: Solve for x
    x = 2,021,449.48/1,642.25
  6. Step 6: Final answer
    x = 1,230.90

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Half scale
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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.