Home / 1,081.11-1,491.69-639

Finding the Fourth Proportional to 1,081.11, 1,491.69 and 639

Calculator

Solution

The fourth proportional to 1,081.11, 1,491.69 and 639 is: 881.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,081.11 : 1,491.69 = 639 : x
  2. Step 2: Convert to fraction form
    1,081.11/1,491.69 = 639/x
  3. Step 3: Cross multiply
    1,081.11x = 1,491.69 × 639
  4. Step 4: Simplify right side
    1,081.11x = 953,189.91
  5. Step 5: Solve for x
    x = 953,189.91/1,081.11
  6. Step 6: Final answer
    x = 881.68

Related Problems

Find fourth proportional to 540.56, 745.85 and 319.50
Half scale
Find fourth proportional to 2,162.22, 2,983.38 and 1,278
Double scale
Find fourth proportional to 1,082.11, 1,493.07 and 640
Similar ratio
Find fourth proportional to 1,621.67, 2,237.54 and 958.50
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.