Home / 774.20-1,161.30-687.80

Finding the Fourth Proportional to 774.20, 1,161.30 and 687.80

Calculator

Solution

The fourth proportional to 774.20, 1,161.30 and 687.80 is: 1,031.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    774.20 : 1,161.30 = 687.80 : x
  2. Step 2: Convert to fraction form
    774.20/1,161.30 = 687.80/x
  3. Step 3: Cross multiply
    774.20x = 1,161.30 × 687.80
  4. Step 4: Simplify right side
    774.20x = 798,742.14
  5. Step 5: Solve for x
    x = 798,742.14/774.20
  6. Step 6: Final answer
    x = 1,031.70

Related Problems

Find fourth proportional to 387.10, 580.65 and 343.90
Half scale
Find fourth proportional to 1,548.40, 2,322.60 and 1,375.60
Double scale
Find fourth proportional to 775.20, 1,162.80 and 688.80
Similar ratio
Find fourth proportional to 1,161.30, 1,741.95 and 1,031.70
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.