Respuesta :

Answer:

I think 12 is the answer

Step-by-step explanation:

In ∆ QOP

R and S is the midpoint of OQ and PQ

and RS is parallel to OP

Therefore , By BPT

∆QRS is similar to ∆ QOP

let QS length be 1 unit

therefore , QP is 2 unit ( because QS is half of QP )

RS / OP = QS / QP

18-4x / -9+7x = 1 / 2

after cross multiplying

36-8x = -9+7x

36+9 = 7x+8x

45 = 15x

x=3

we have OP length = -9+7x

put the value of x in above equation

-9+7×3

-9+21

12