Consider the arithmetic sequence 3,8,13,18 find s15

This is an arithmetic sequence since there is a common difference between each term. In this case, adding  

5

to the previous term in the sequence gives the next term. In other words,  

a

n

=

a

1

+

d

(

n

−

1

)

.

Arithmetic Sequence:  

d

=

5

This is the formula of an arithmetic sequence.

a

n

=

a

1

+

d

(

n

−

1

)

Substitute in the values of  

a

1

=

3

and  

d

=

5

.

a

n

=

3

+

(

5

)

(

n

−

1

)

Simplify each term.

Tap for more steps...

a

n

=

3

+

5

n

−

5

Subtract  

5

from  

3

.

a

n

=

5

n

−

2

Step-by-step explanation:

b. 24 mm

step-by-step explanation:

use the pythagorean theorem.

a^2 + b^2 = c^2

a^2 + 7^2 = 25^2

a^2 + 49 = 625

a^2 = 576

a = 24

answer: b. 24 mm

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5