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Finding the Fourth Proportional to 1,420.80, 1,959.36 and 831.36

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Solution

The fourth proportional to 1,420.80, 1,959.36 and 831.36 is: 1,146.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.80 : 1,959.36 = 831.36 : x
  2. Step 2: Convert to fraction form
    1,420.80/1,959.36 = 831.36/x
  3. Step 3: Cross multiply
    1,420.80x = 1,959.36 × 831.36
  4. Step 4: Simplify right side
    1,420.80x = 1,628,933.53
  5. Step 5: Solve for x
    x = 1,628,933.53/1,420.80
  6. Step 6: Final answer
    x = 1,146.49

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1.5x scale

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.