Find the sum of the first 42 terms of the following series, to the nearest integer.
2,7,12,...

Step-by-step explanation:

Find the sum of the first 42 terms of the following series, to the nearest integer.

2,7,12

Solution

The sum is given by  

SUM_n=n/2*(a_1+a_n)

a_n=a_1+(n-1)d

a_1=2,   n=42,     d=5

The 42nd term is therefore given by  

a_42=2+(42-1)5=207

SUM_42=42/2*(2+207)=21*209=4389

The sum of the first 42 terms of the series, therefore, is 4389

∠lno ≅ ∠lnm

∠oln ≅ ∠mln

step-by-step explanation:

given   that triangle lno is congruent to triangle lnm.

we have to fill up the blanks in the given question.

according to above order of congruency   kept in mind we can say that

∠lno ≅ ∠lnm

∠oln ≅ ∠mln

ln ≅ ln due to common in both.

hence, by sas congruency,

the side angle side rule   states that if two sides and the included angle of one triangle are congruent to another triangle, then these two triangles are congruent.

160 cm

step-by-step explanation:

you have to add all the sides together