Can someone find "BC" for me plz?

BC = 104

Step-by-step explanation:

By the SAS postulate, ΔBDA and ΔBDC are congruent, meaning that each of the corresponding sides are equal in length.

BD = BD

AD = CD

BA = BC

If we know BA = 21x - 1 and BC = 9x + 59, then we can set them equal to each other and solve for "x".

BA = BC

21x - 1 = 9x + 59

21x = 9x + 60                     Added 1 to both sides

12x = 60                             Subtracted 9x from both sides

x = 60/12                            Divided both sides by 12

x = 5                                   Reduced fraction, solved for "x"

To find BC, substitute x = 5 into the equation for BC.

BC = 9x + 59

BC = 9(5) + 59                    Substituted "x" for 5

BC = 45 + 59                      Multiplied 9 and 5

BC = 104                            Added, solved for BC

∴ BC = 104

we know that

applying the law of sines

°

so

∠j=18°

∠k=29°

∠l=180-(18+29)=133°

the answer part a) is

the measure of angle k is  ≈29°

part b)  the measure of angle k could also be

(180-29)=151°

so

∠j=18°

∠k=151°

∠l=180-(18+151)=11°

the answer part b) is

the measure of angle k could also be 151°

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