Home / 419.20-628.80-199.84

Finding the Fourth Proportional to 419.20, 628.80 and 199.84

Calculator

Solution

The fourth proportional to 419.20, 628.80 and 199.84 is: 299.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.20 : 628.80 = 199.84 : x
  2. Step 2: Convert to fraction form
    419.20/628.80 = 199.84/x
  3. Step 3: Cross multiply
    419.20x = 628.80 × 199.84
  4. Step 4: Simplify right side
    419.20x = 125,658.39
  5. Step 5: Solve for x
    x = 125,658.39/419.20
  6. Step 6: Final answer
    x = 299.76

Related Problems

Find fourth proportional to 209.60, 314.40 and 99.92
Half scale
Find fourth proportional to 838.39, 1,257.59 and 399.68
Double scale
Find fourth proportional to 420.20, 630.30 and 200.84
Similar ratio
Find fourth proportional to 628.79, 943.19 and 299.76
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.