If you want the strip around the mat:
x=strip of mat
2(20+2x)+2(15+2x)=102
Distribute
40+4x+30+4x=102
Combine like terms
70+8x=102
Subtract 70
8x=32
Divide by 8
x=4
If you want the whole width of the mat:
w=15+x
w=15+2*4
w=23
Answer:
x = -6
Step-by-step explanation:
Angle A is 24*
Angle B is 134*
Angle C is 22*
A: 8293
B:8393738283737383838373738
C:82837282073
D:9193