Question

19. If the perimeter of the figure given is 57 cm, find the
perimeter of the triangle in the figure.
2p cm
бp cm
7p cm
Зp cm
30 cm
45 cm
O 39 cm
o 3 cm​

Answer 1

Solution:

(a) Perimeter = Sum of all side

= 4 + 2 + 1 + 5

= 12 cm

Perimeter of fig(a) is 12 cm

(b) Perimeter = Sum of all side

= 23 + 35 + 40 + 35

= 133 cm

Perimeter of fig(b) is 133 cm.

(c) Perimeter = Sum of all side

= 15 + 15 + 15 + 15

= 60 cm

Perimeter of fig(c) is 60 cm.

(d) Perimeter = Sum of all sides

= 4 + 4 + 4 + 4 + 4

= 20 cm

Perimeter of fig(d) is 20 cm.

(e) Perimeter = Sum of all sides

= 2.5 + 2.5 + 0.5 + 0.5 + 4 + 4 + 1

= 5 + 1 + 9

= 15 cm

Perimeter of fig(e) is 15 cm.

(f) Perimeter = Sum of all side

= 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3 + 4 + 1 + 3 + 2 + 3

= 52 cm

Perimeter of fig(f) is 52 cm.

Answer 2

Step-by-step explanation:

Given,

0.5x + 0.7y = 0.74

0.3x - 0.5y = 0.5

Now,

Multiply (1) and (2) by 100,

50x + 70y = 74

30x + 50y = 50

Now,

From (3) we have,

50x = 74 - 70y

x = (74 - 70y)/50

Here,

Putting value of x in (4),

30x + 50y = 50

30 (74 - 70y)/50 + 50y = 50

3(74 - 70y)/5 + 50y = 50

[(222 - 210y) + 250y]/5 = 50

[222 - 210y + 250y] = 50 × 5

40y = 250 - 222

40y = 28

y = 28/40

y = 7/10

y = 0.7

Now,

Substituting value of y in (5),

x = (74 - 70y)/50

x = (74 - 70 × 0.7)/50

x = (74 - 49)/50

x = 25/50

x = 5/10

x = 0.5

Therefore,

x = 0.5 and y = 0.7