The total height the next three highest can jump is 78 inches because 23 + 27 + 28 = <<23+27+28=78>>78
The average height they can jump is 26 inches because 78 / 3 = <<78/3=26>>26
Ravi can jump 39 inches high because 26 x 1.5 = <<26*1.5=39>>39
#### 39