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Finding the Fourth Proportional to 1,212.12, 1,817.71 and 390.17

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Solution

The fourth proportional to 1,212.12, 1,817.71 and 390.17 is: 585.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.12 : 1,817.71 = 390.17 : x
  2. Step 2: Convert to fraction form
    1,212.12/1,817.71 = 390.17/x
  3. Step 3: Cross multiply
    1,212.12x = 1,817.71 × 390.17
  4. Step 4: Simplify right side
    1,212.12x = 709,215.91
  5. Step 5: Solve for x
    x = 709,215.91/1,212.12
  6. Step 6: Final answer
    x = 585.10

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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.