Home / 772.20-1,064.88-640.80

Finding the Fourth Proportional to 772.20, 1,064.88 and 640.80

Calculator

Solution

The fourth proportional to 772.20, 1,064.88 and 640.80 is: 883.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.20 : 1,064.88 = 640.80 : x
  2. Step 2: Convert to fraction form
    772.20/1,064.88 = 640.80/x
  3. Step 3: Cross multiply
    772.20x = 1,064.88 × 640.80
  4. Step 4: Simplify right side
    772.20x = 682,375.10
  5. Step 5: Solve for x
    x = 682,375.10/772.20
  6. Step 6: Final answer
    x = 883.68

Related Problems

Find fourth proportional to 386.10, 532.44 and 320.40
Half scale
Find fourth proportional to 1,544.40, 2,129.76 and 1,281.60
Double scale
Find fourth proportional to 773.20, 1,066.26 and 641.80
Similar ratio
Find fourth proportional to 1,158.30, 1,597.32 and 961.20
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.