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Finding the Fourth Proportional to 1,130.80, 1,560.80 and 689

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Solution

The fourth proportional to 1,130.80, 1,560.80 and 689 is: 951.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,130.80 : 1,560.80 = 689 : x
  2. Step 2: Convert to fraction form
    1,130.80/1,560.80 = 689/x
  3. Step 3: Cross multiply
    1,130.80x = 1,560.80 × 689
  4. Step 4: Simplify right side
    1,130.80x = 1,075,391.20
  5. Step 5: Solve for x
    x = 1,075,391.20/1,130.80
  6. Step 6: Final answer
    x = 951.00

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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.