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Finding the Fourth Proportional to 1,213.30, 1,821.30 and 665.50

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Solution

The fourth proportional to 1,213.30, 1,821.30 and 665.50 is: 998.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.30 : 1,821.30 = 665.50 : x
  2. Step 2: Convert to fraction form
    1,213.30/1,821.30 = 665.50/x
  3. Step 3: Cross multiply
    1,213.30x = 1,821.30 × 665.50
  4. Step 4: Simplify right side
    1,213.30x = 1,212,075.15
  5. Step 5: Solve for x
    x = 1,212,075.15/1,213.30
  6. Step 6: Final answer
    x = 998.99

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Double 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.