18. If x, 1, z are in A. P. and x, 2, z are in G. P. then x, 4, z are in
1. G. P.
2. H. P.
3. A. P.
4. none​

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.

c

step-by-step explanation:

none of these

step-by-step explanation:

23 + 34 add up to 57 so just inform the teacher of this really stupid mistake