Answer:
The correct option is C ) 109.5°
Therefore,

Step-by-step explanation:
Given:
In Triangle DEF
d = 10
e = 18
f = 12
To Find
angle E = ?
Solution:
In Triangle DEF , Cosine Rule says

Substituting the values we get


Therefore,

............As it is in Second Quadrant
Therefore,

All it's asking is: How many cubic inches are there in 22 gallons ? And it already GAVE us the conversion factor !
The conversion factor is . . . . . 1 gallon = 231 cubic inches
Multiply each side by 22: 22 gallons = 22 x (231 cubic inches)
22 x 231 = 5,082
22 gallons = 5,082 cubic inches
If you empty a full 22-gallon tank out through that flow meter, the meter will register 5,082 cubic inches when the tank is empty.
Four times the sum of x and two
39° because a right angle adds up to 90°
Twenty-five times two = fifty