Find the sum of the first 63 terms of –19, -13, -7 …

You can tell this is an arithmetic sequence because it is a list of terms beginning with -19 that increase by 6 each term. Because of this, we can use the formula for the sum of an arithmetic sequence, which is:

In this case, we can see that , , and . Thus, we can use the formula:

Our answer is 10,521.

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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step-by-step explanation: