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Finding the Fourth Proportional to 1,113.40, 1,671.70 and 870.20

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Solution

The fourth proportional to 1,113.40, 1,671.70 and 870.20 is: 1,306.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,113.40 : 1,671.70 = 870.20 : x
  2. Step 2: Convert to fraction form
    1,113.40/1,671.70 = 870.20/x
  3. Step 3: Cross multiply
    1,113.40x = 1,671.70 × 870.20
  4. Step 4: Simplify right side
    1,113.40x = 1,454,713.34
  5. Step 5: Solve for x
    x = 1,454,713.34/1,113.40
  6. Step 6: Final answer
    x = 1,306.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.