Answer:
a.
Step-by-step explanation:
Answer: 9
Step-by-step explanation:
s = 7
k = 4
x = 6
7 - 4 + 6
3 + 6
9
5x - 18 + x = 90
6x = 108
x = 18 degrees
Answer: 
Step-by-step explanation:
1. Let's write the following formula for calculate the area of a rectangle:

Where
is the lenght (the longer side) and
is the width (the shorter side).
2. You know that the length is 2.5 times as long as the other side, which indicates a multiplication. Then:

3. So, you must substitute
into the equation for calculate the area of the rectangle and then you must simplify.
4. Then, you obtain the following expression:

Answer:
The answers is below in bold.
Step-by-step explanation:
(a) A = 180 - 25.6 - 124.4 = 30 degrees.
Next use the Sine Rule:
b / sin B = c / sin C
b / sin 25.6 = 39.2/sin 124.4
b = (39.2 * sin 25.6) / sin 124.4
b = 20.53 m.
Also
a / sin A = c / sin C
a / sin 30 = 39.2 / sin 124.4
a = (39.2 * sin 30 / sin 124.4
a = 23.75 m.
b). This is solved in a similar way to (a).
First find angle C using the sine rule.
Then you will know angle A from the 180 degree Rule.
Then you can find the length of a using the Sine Rule.