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Finding the Fourth Proportional to 1,221.46, 1,831.10 and 643.66

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Solution

The fourth proportional to 1,221.46, 1,831.10 and 643.66 is: 964.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.46 : 1,831.10 = 643.66 : x
  2. Step 2: Convert to fraction form
    1,221.46/1,831.10 = 643.66/x
  3. Step 3: Cross multiply
    1,221.46x = 1,831.10 × 643.66
  4. Step 4: Simplify right side
    1,221.46x = 1,178,605.83
  5. Step 5: Solve for x
    x = 1,178,605.83/1,221.46
  6. Step 6: Final answer
    x = 964.92

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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.