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Finding the Fourth Proportional to 1,036.40, 1,428.84 and 687.12

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Solution

The fourth proportional to 1,036.40, 1,428.84 and 687.12 is: 947.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,036.40 : 1,428.84 = 687.12 : x
  2. Step 2: Convert to fraction form
    1,036.40/1,428.84 = 687.12/x
  3. Step 3: Cross multiply
    1,036.40x = 1,428.84 × 687.12
  4. Step 4: Simplify right side
    1,036.40x = 981,784.54
  5. Step 5: Solve for x
    x = 981,784.54/1,036.40
  6. Step 6: Final answer
    x = 947.30

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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.