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Finding the Fourth Proportional to 1,080.40, 1,490.72 and 687.28

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Solution

The fourth proportional to 1,080.40, 1,490.72 and 687.28 is: 948.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,080.40 : 1,490.72 = 687.28 : x
  2. Step 2: Convert to fraction form
    1,080.40/1,490.72 = 687.28/x
  3. Step 3: Cross multiply
    1,080.40x = 1,490.72 × 687.28
  4. Step 4: Simplify right side
    1,080.40x = 1,024,542.04
  5. Step 5: Solve for x
    x = 1,024,542.04/1,080.40
  6. Step 6: Final answer
    x = 948.30

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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.