Your answer will be -9 !!
I believe the answer is A
Answer:
(21 and 54): 3
(55 and 90): 5
(16 and 30): 2
(42 and 91): 7
(66 and 121): 11
Step-by-step explanation:
For question 4, 
Question 5. Option a and question 6. Option j
Step-by-step explanation:
Step 1:
The three basic formula needed to solve these questions are:

Step 2:
Using the above formula, we solve the following values









Step 3:
For question 5, The triangle's angle = 23°, opposite side = BC inches and hypotenuse = 4 inches.

SO BC is 1.5628 inches, rounding this off to the nearest tenth, we get BC = 1.6 inches which is option a.
Step 4:
For question 6, The triangle's angle = 50°, opposite side = QR m the adjacent side = 8.1 m.

SO QR is 9.65277 meters, rounding this off to the nearest tenth, we get QR = 9.7 inches which is option j.
A because 16x9=144 and 4x6=24 and 144-24=120