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construct triangle ABC, where AB = 6cm, Angle BAC = 50 degrees, Angle ABC = 70 degrees measure the length of BC to 1 d.p helppppp

User Spauny
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1 Answer

4 votes

Answer: BC = 5.3

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Step-by-step explanation:

Side AB is opposite angle C.

Convention is that the lowercase letters represent the side lengths, and they are opposite the uppercase angles.

  • Angle A is opposite side 'a'
  • Angle B is opposite side 'b'
  • Angle C is opposite side 'c'

In short, side AB can be relabeled as side c. Therefore, c = 6.

Angle BAC can be shortened to simply saying angle A.

Angle ABC is shortened to angle B.

The angle names are drawn directly from the middle letter.

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Here's the given info:

  • side c = 6
  • angle A = 50
  • angle B = 70

Let's use the idea that all 3 angles of a triangle must add to 180 to find angle C.

A+B+C = 180

C = 180-A-B

C = 180-50-70

C = 60

Now let's use the law of sines to determine side 'a'.

a/sin(A) = c/sin(C)

a/sin(50) = 6/sin(60)

a = sin(50)*6/sin(60)

a = 5.3073115853515 approximately

a = 5.3 after rounding to one decimal place

Segment BC is approximately 5.3 cm long.

User Mike McLin
by
4.9k points