Home / 486.21-729.21-139.54

Finding the Fourth Proportional to 486.21, 729.21 and 139.54

Calculator

Solution

The fourth proportional to 486.21, 729.21 and 139.54 is: 209.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.21 : 729.21 = 139.54 : x
  2. Step 2: Convert to fraction form
    486.21/729.21 = 139.54/x
  3. Step 3: Cross multiply
    486.21x = 729.21 × 139.54
  4. Step 4: Simplify right side
    486.21x = 101,755.09
  5. Step 5: Solve for x
    x = 101,755.09/486.21
  6. Step 6: Final answer
    x = 209.28

Related Problems

Find fourth proportional to 243.11, 364.60 and 69.77
Half scale
Find fourth proportional to 972.42, 1,458.41 and 279.09
Double scale
Find fourth proportional to 487.21, 730.70 and 140.54
Similar ratio
Find fourth proportional to 729.32, 1,093.81 and 209.31
1.5x scale

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.