Home / 520.80-779.40-520.80

Finding the Fourth Proportional to 520.80, 779.40 and 520.80

Calculator

Solution

The fourth proportional to 520.80, 779.40 and 520.80 is: 779.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.80 : 779.40 = 520.80 : x
  2. Step 2: Convert to fraction form
    520.80/779.40 = 520.80/x
  3. Step 3: Cross multiply
    520.80x = 779.40 × 520.80
  4. Step 4: Simplify right side
    520.80x = 405,911.52
  5. Step 5: Solve for x
    x = 405,911.52/520.80
  6. Step 6: Final answer
    x = 779.40

Related Problems

Find fourth proportional to 260.40, 389.70 and 260.40
Half scale
Find fourth proportional to 1,041.60, 1,558.80 and 1,041.60
Double scale
Find fourth proportional to 521.80, 780.90 and 521.80
Similar ratio
Find fourth proportional to 781.20, 1,169.10 and 781.20
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.