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Finding the Fourth Proportional to 1,129.80, 1,561.12 and 870.08

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Solution

The fourth proportional to 1,129.80, 1,561.12 and 870.08 is: 1,202.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,129.80 : 1,561.12 = 870.08 : x
  2. Step 2: Convert to fraction form
    1,129.80/1,561.12 = 870.08/x
  3. Step 3: Cross multiply
    1,129.80x = 1,561.12 × 870.08
  4. Step 4: Simplify right side
    1,129.80x = 1,358,299.29
  5. Step 5: Solve for x
    x = 1,358,299.29/1,129.80
  6. Step 6: Final answer
    x = 1,202.25

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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.