Answer:
the third side is 40 m long
Step-by-step explanation:
The perimeter of the triangle is the sum of its three sides, and they give you what that value in meters is (120 m)
Your are given the length of two of them: 30 m and 50 m, and need to find the third one (let's call it "x" for this unknown side)
Now set the following equation:
Perimeter = side 1 + side 2 + side 3 --> replace these with the info you know
120 m = 30 m + 50 m + x --> add 30 m and 50 m obtaining 80 m
120 m = 80 m + x --> now solve for x (isolate the x on one side) by subtracting 80 m from both sides
120 m - 80 m = x --> perform the subtraction 120 m - 80 m = 40 m
40 m = x
Which tells us that the third unknown side has a length of 40 m
One may note you never quite asked anything, now, assuming simplification,
Answer:
The third side is around 58.043
Step-by-step explanation:
Use the law of cosines: 
Plug in the two sides we know (into a and b) and the angle we know (into angle C).
Thus:
Use a calculator:


(Note: Make sure you're in Degrees mode.)
Answer:
x = 17 and y = 10
Step-by-step explanation:
ABCD is a parallelogram
So AB = CD and AD = BC
so
3x - 9 = 42
3x = 51
x = 17
and
4y - 3 = 37
4y = 40
y = 10
Answer
x = 17 and y = 10
Set up a x/100 = (14-48)/48 = -34/48 Multiply the cross 48x = -3400 x = 70.8333 so around -70.83% change