1. The diagram below shows a triangle ABC, where AB = 8 cm, AC = 6 cm, and angle ACB = 60 degrees - HSC - SSCE Mathematics Advanced - Question 1 - 2020 - Paper 1
Question 1
1. The diagram below shows a triangle ABC, where AB = 8 cm, AC = 6 cm, and angle ACB = 60 degrees.
(Insert diagram here)
(a) Calculate the length of side BC.... show full transcript
Worked Solution & Example Answer:1. The diagram below shows a triangle ABC, where AB = 8 cm, AC = 6 cm, and angle ACB = 60 degrees - HSC - SSCE Mathematics Advanced - Question 1 - 2020 - Paper 1
Step 1
Calculate the length of side BC.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the length of side BC, we will apply the Law of Cosines, which states:
c2=a2+b2−2ab⋅cos(C)
In our case:
Let AB = c = 8 cm,
AC = b = 6 cm,
angle ACB = C = 60 degrees,
BC = a (unknown).
Inserting these values into the formula gives:
BC2=82+62−2⋅8⋅6⋅cos(60∘)BC2=64+36−2⋅8⋅6⋅21BC2=100−48BC2=52
$$BC = \sqrt{52} \approx 7.21 \text{ cm}.$
Step 2
Calculate the area of triangle ABC.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The area of triangle ABC can be calculated using the formula:
Area=21⋅a⋅b⋅sin(C)
Substituting the known values:
a = 8 cm,
b = 6 cm,
angle C = 60 degrees.
Thus, the area becomes:
Area=21⋅8⋅6⋅sin(60∘)Area=21⋅8⋅6⋅23
$$\text{Area} = 24\sqrt{3} \approx 41.57 \text{ cm}^2.$