Home / 519.60-779.40-438.60

Finding the Fourth Proportional to 519.60, 779.40 and 438.60

Calculator

Solution

The fourth proportional to 519.60, 779.40 and 438.60 is: 657.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    519.60 : 779.40 = 438.60 : x
  2. Step 2: Convert to fraction form
    519.60/779.40 = 438.60/x
  3. Step 3: Cross multiply
    519.60x = 779.40 × 438.60
  4. Step 4: Simplify right side
    519.60x = 341,844.84
  5. Step 5: Solve for x
    x = 341,844.84/519.60
  6. Step 6: Final answer
    x = 657.90

Related Problems

Find fourth proportional to 259.80, 389.70 and 219.30
Half scale
Find fourth proportional to 1,039.20, 1,558.80 and 877.20
Double scale
Find fourth proportional to 520.60, 780.90 and 439.60
Similar ratio
Find fourth proportional to 779.40, 1,169.10 and 657.90
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.