Home / 863.80-1,289.82-688.50

Finding the Fourth Proportional to 863.80, 1,289.82 and 688.50

Calculator

Solution

The fourth proportional to 863.80, 1,289.82 and 688.50 is: 1,028.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    863.80 : 1,289.82 = 688.50 : x
  2. Step 2: Convert to fraction form
    863.80/1,289.82 = 688.50/x
  3. Step 3: Cross multiply
    863.80x = 1,289.82 × 688.50
  4. Step 4: Simplify right side
    863.80x = 888,043.65
  5. Step 5: Solve for x
    x = 888,043.65/863.80
  6. Step 6: Final answer
    x = 1,028.07

Related Problems

Find fourth proportional to 431.90, 644.91 and 344.25
Half scale
Find fourth proportional to 1,727.60, 2,579.65 and 1,377
Double scale
Find fourth proportional to 864.80, 1,291.32 and 689.50
Similar ratio
Find fourth proportional to 1,295.70, 1,934.74 and 1,032.75
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.