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Finding the Fourth Proportional to 1,210.91, 1,670.91 and 686.93

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Solution

The fourth proportional to 1,210.91, 1,670.91 and 686.93 is: 947.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.91 : 1,670.91 = 686.93 : x
  2. Step 2: Convert to fraction form
    1,210.91/1,670.91 = 686.93/x
  3. Step 3: Cross multiply
    1,210.91x = 1,670.91 × 686.93
  4. Step 4: Simplify right side
    1,210.91x = 1,147,798.21
  5. Step 5: Solve for x
    x = 1,147,798.21/1,210.91
  6. Step 6: Final answer
    x = 947.88

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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.