Let's represent the numbers by : x, x+1, x+2, x+3
x+x+1+x+2+x+3=40 The third number in the sequence is x+2
4x+6=40 8.5+2=10.5
4x+6-6=40-6 Therefore the third number in the sequence is
4x=34 10.5
4x/4=34/4
x=8.5
Answer:
∠ WUV = 36°
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ VWX is an exterior angle of the triangle, thus
8x - 18 = 2x + 8 + 3x + 16
8x - 18 = 5x + 24 ( subtract 5x from both sides )
3x - 18 = 24 ( add 18 to both sides )
3x = 42 ( divide both sides by 3 )
x = 14
Thus
∠ WUV = 2x + 8 = 2(14) + 8 = 28 + 8 = 36°
B :81 EXPLANATION
The angle with the greatest measure corresponds to the longest:
Since we know the three side lengths, we use the cosine rule to obtain;
{a}^{2} = {b}^{2} + {c}^{2} - 2bc \cos(A)
where a=21, b=18 and c=14
{21}^{2} = {18}^{2} + {14}^{2} - 2 \times 18 \times 14\cos(A)
44 1= 324+ 196 - 504\cos(A)
44 1= 520 - 504\cos(A)
44 1 - 520 = - 504\cos(A)
- 79 = - 504\cos(A)
\cos(A) = 0.1567
A = \cos ^{ - 1} (0.1567) = 80.98 \degree
