Answer:
x = 13
Step-by-step explanation:
Sum or interior angles of a triangle is 180,
6x + 19 + 5x - 15 + 3x - 6 = 180
6x + 5x + 3x + 19 - 15 - 6 = 180
14x + 19 - 21 = 180
14x - 2 = 180
14x = 180 + 2
14x = 182
x = 182 / 14
x = 13
Answer:
100
Step-by-step explanation:
We have the sum of first n terms of an AP,
Sn = n/2 [2a+(n−1)d]
Given,
36= 6/2 [2a+(6−1)d]
12=2a+5d ---------(1)
256= 16/2 [2a+(16−1)d]
32=2a+15d ---------(2)
Subtracting, (1) from (2)
32−12=2a+15d−(2a+5d)
20=10d ⟹d=2
Substituting for d in (1),
12=2a+5(2)=2(a+5)
6=a+5 ⟹a=1
∴ The sum of first 10 terms of an AP,
S10 = 10/2 [2(1)+(10−1)2]
S10 =5[2+18]
S10 =100
This is the sum of the first 10 terms.
Hope it will help.
