Home / 399.21-550.80-251.79

Finding the Fourth Proportional to 399.21, 550.80 and 251.79

Calculator

Solution

The fourth proportional to 399.21, 550.80 and 251.79 is: 347.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.21 : 550.80 = 251.79 : x
  2. Step 2: Convert to fraction form
    399.21/550.80 = 251.79/x
  3. Step 3: Cross multiply
    399.21x = 550.80 × 251.79
  4. Step 4: Simplify right side
    399.21x = 138,685.93
  5. Step 5: Solve for x
    x = 138,685.93/399.21
  6. Step 6: Final answer
    x = 347.40

Related Problems

Find fourth proportional to 199.61, 275.40 and 125.90
Half scale
Find fourth proportional to 798.42, 1,101.60 and 503.58
Double scale
Find fourth proportional to 400.21, 552.18 and 252.79
Similar ratio
Find fourth proportional to 598.82, 826.20 and 377.69
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.