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Finding the Fourth Proportional to 1,376.80, 1,899.80 and 779.28

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Solution

The fourth proportional to 1,376.80, 1,899.80 and 779.28 is: 1,075.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,376.80 : 1,899.80 = 779.28 : x
  2. Step 2: Convert to fraction form
    1,376.80/1,899.80 = 779.28/x
  3. Step 3: Cross multiply
    1,376.80x = 1,899.80 × 779.28
  4. Step 4: Simplify right side
    1,376.80x = 1,480,476.14
  5. Step 5: Solve for x
    x = 1,480,476.14/1,376.80
  6. Step 6: Final answer
    x = 1,075.30

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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.