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Finding the Fourth Proportional to 1,011.80, 1,395.69 and 638.12

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Solution

The fourth proportional to 1,011.80, 1,395.69 and 638.12 is: 880.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,011.80 : 1,395.69 = 638.12 : x
  2. Step 2: Convert to fraction form
    1,011.80/1,395.69 = 638.12/x
  3. Step 3: Cross multiply
    1,011.80x = 1,395.69 × 638.12
  4. Step 4: Simplify right side
    1,011.80x = 890,617.70
  5. Step 5: Solve for x
    x = 890,617.70/1,011.80
  6. Step 6: Final answer
    x = 880.23

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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.