Home / 619.88-855.74-399.20

Finding the Fourth Proportional to 619.88, 855.74 and 399.20

Calculator

Solution

The fourth proportional to 619.88, 855.74 and 399.20 is: 551.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    619.88 : 855.74 = 399.20 : x
  2. Step 2: Convert to fraction form
    619.88/855.74 = 399.20/x
  3. Step 3: Cross multiply
    619.88x = 855.74 × 399.20
  4. Step 4: Simplify right side
    619.88x = 341,611.41
  5. Step 5: Solve for x
    x = 341,611.41/619.88
  6. Step 6: Final answer
    x = 551.09

Related Problems

Find fourth proportional to 309.94, 427.87 and 199.60
Half scale
Find fourth proportional to 1,239.76, 1,711.48 and 798.40
Double scale
Find fourth proportional to 620.88, 857.12 and 400.20
Similar ratio
Find fourth proportional to 929.82, 1,283.61 and 598.80
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.