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Finding the Fourth Proportional to 1,210.81, 1,670.73 and 686.87

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Solution

The fourth proportional to 1,210.81, 1,670.73 and 686.87 is: 947.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.81 : 1,670.73 = 686.87 : x
  2. Step 2: Convert to fraction form
    1,210.81/1,670.73 = 686.87/x
  3. Step 3: Cross multiply
    1,210.81x = 1,670.73 × 686.87
  4. Step 4: Simplify right side
    1,210.81x = 1,147,574.32
  5. Step 5: Solve for x
    x = 1,147,574.32/1,210.81
  6. Step 6: Final answer
    x = 947.77

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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.