Its adding the current number by the previous number so the next three would be 21,34,55
Answer:

Step-by-step explanation:
hey there!!!
we know already that the area of a triangle is given as

where b= base
and h= heigth
Given that the height is 5 times more than twice it base
let h= 2b+5
Now we substitute h=2b+5 in the area of the triangle


Answer:
1.375
Step-by-step explanation: