Home / 409.28-611.20-385.28

Finding the Fourth Proportional to 409.28, 611.20 and 385.28

Calculator

Solution

The fourth proportional to 409.28, 611.20 and 385.28 is: 575.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    409.28 : 611.20 = 385.28 : x
  2. Step 2: Convert to fraction form
    409.28/611.20 = 385.28/x
  3. Step 3: Cross multiply
    409.28x = 611.20 × 385.28
  4. Step 4: Simplify right side
    409.28x = 235,483.14
  5. Step 5: Solve for x
    x = 235,483.14/409.28
  6. Step 6: Final answer
    x = 575.36

Related Problems

Find fourth proportional to 204.64, 305.60 and 192.64
Half scale
Find fourth proportional to 818.56, 1,222.40 and 770.56
Double scale
Find fourth proportional to 410.28, 612.69 and 386.28
Similar ratio
Find fourth proportional to 613.92, 916.80 and 577.92
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.