Home / 618.88-854.36-398.20

Finding the Fourth Proportional to 618.88, 854.36 and 398.20

Calculator

Solution

The fourth proportional to 618.88, 854.36 and 398.20 is: 549.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.88 : 854.36 = 398.20 : x
  2. Step 2: Convert to fraction form
    618.88/854.36 = 398.20/x
  3. Step 3: Cross multiply
    618.88x = 854.36 × 398.20
  4. Step 4: Simplify right side
    618.88x = 340,206.15
  5. Step 5: Solve for x
    x = 340,206.15/618.88
  6. Step 6: Final answer
    x = 549.71

Related Problems

Find fourth proportional to 309.44, 427.18 and 199.10
Half scale
Find fourth proportional to 1,237.76, 1,708.72 and 796.40
Double scale
Find fourth proportional to 619.88, 855.74 and 399.20
Similar ratio
Find fourth proportional to 928.32, 1,281.54 and 597.30
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.