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Finding the Fourth Proportional to 809.40, 1,212.18 and 718.20

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Solution

The fourth proportional to 809.40, 1,212.18 and 718.20 is: 1,075.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.40 : 1,212.18 = 718.20 : x
  2. Step 2: Convert to fraction form
    809.40/1,212.18 = 718.20/x
  3. Step 3: Cross multiply
    809.40x = 1,212.18 × 718.20
  4. Step 4: Simplify right side
    809.40x = 870,587.68
  5. Step 5: Solve for x
    x = 870,587.68/809.40
  6. Step 6: Final answer
    x = 1,075.60

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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.