Question

Which equation relates the number of triangles in the figure (n) to the perimeter of the figure (p)

a.P=10n+14
b. P=10n+7
c.P=7n+10
d. P=7n+20.

the Perimeter of the triangles are 27. 34. 41.

Answer 1

Option d is correct.

Equation : P=7n+20.

Explanation;

Given the perimeter of each figure is;

Perimeter of triangle is equal to the sum of all the sides of a triangle.

Perimeter of 1 triangle is 21

Perimeter of 2 triangle is 34 and

Perimeter of 3 triangle is 41

Let n be the number of figure and P be the perimeter of the figure;

the only equation which satisfy the given perimeter is;

`P=7n+20`

Check:

for n =1 which means 1 triangle then;

`P =7n+20 = 7 \cdot 1 +20 = 7+20 = 27`

for n = 2 , [ i.e 2 triangle]

`P =7n+20 = 7 \cdot 2 +20 = 14+20 = 34`

and for n =3 [i.e, 3 triangles]

`P =7n+20 = 7 \cdot 3 +20 = 21+20 = 41`

Therefore, the equation P =7n+20 relates the number of triangles in the figure(n) to the perimeter of the figure(P).