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Finding the Fourth Proportional to 1,211.71, 1,817.64 and 390.12

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Solution

The fourth proportional to 1,211.71, 1,817.64 and 390.12 is: 585.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.71 : 1,817.64 = 390.12 : x
  2. Step 2: Convert to fraction form
    1,211.71/1,817.64 = 390.12/x
  3. Step 3: Cross multiply
    1,211.71x = 1,817.64 × 390.12
  4. Step 4: Simplify right side
    1,211.71x = 709,090.90
  5. Step 5: Solve for x
    x = 709,090.90/1,211.71
  6. Step 6: Final answer
    x = 585.20

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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.