Home / 1,209.21-1,666.75-815.55

Finding the Fourth Proportional to 1,209.21, 1,666.75 and 815.55

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Solution

The fourth proportional to 1,209.21, 1,666.75 and 815.55 is: 1,124.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.21 : 1,666.75 = 815.55 : x
  2. Step 2: Convert to fraction form
    1,209.21/1,666.75 = 815.55/x
  3. Step 3: Cross multiply
    1,209.21x = 1,666.75 × 815.55
  4. Step 4: Simplify right side
    1,209.21x = 1,359,317.96
  5. Step 5: Solve for x
    x = 1,359,317.96/1,209.21
  6. Step 6: Final answer
    x = 1,124.14

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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.