Home / 1,221-1,685-669

Finding the Fourth Proportional to 1,221, 1,685 and 669

Calculator

Solution

The fourth proportional to 1,221, 1,685 and 669 is: 923.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221 : 1,685 = 669 : x
  2. Step 2: Convert to fraction form
    1,221/1,685 = 669/x
  3. Step 3: Cross multiply
    1,221x = 1,685 × 669
  4. Step 4: Simplify right side
    1,221x = 1,127,265
  5. Step 5: Solve for x
    x = 1,127,265/1,221
  6. Step 6: Final answer
    x = 923.23

Related Problems

Find fourth proportional to 610.50, 842.50 and 334.50
Half scale
Find fourth proportional to 2,442, 3,370 and 1,338
Double scale
Find fourth proportional to 1,222, 1,686.38 and 670
Similar ratio
Find fourth proportional to 1,831.50, 2,527.50 and 1,003.50
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.