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Finding the Fourth Proportional to 1,221.16, 1,684.91 and 690.06

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Solution

The fourth proportional to 1,221.16, 1,684.91 and 690.06 is: 952.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.16 : 1,684.91 = 690.06 : x
  2. Step 2: Convert to fraction form
    1,221.16/1,684.91 = 690.06/x
  3. Step 3: Cross multiply
    1,221.16x = 1,684.91 × 690.06
  4. Step 4: Simplify right side
    1,221.16x = 1,162,688.99
  5. Step 5: Solve for x
    x = 1,162,688.99/1,221.16
  6. Step 6: Final answer
    x = 952.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.