The figure shows a rectangular field ABCD. Bobby walked from A to B to C to D and he covered a distance of 75 cm. Ivory walked from B to C to D to A and she covered a distance of 45 cm.
- What is the perimeter of the field?
- Some construction work was undertaken to the same field and a semi-circular part was removed from it. What Is the perimeter of the field after the construction? (Take π = 227)
(a)
Lets assume Length → L and Breadth → B
Bobby total covered distance
L + L + B = 75
2 L + B = 75 = A1
Ivory total covered distance
B + L + B = 45
2 B + L = 45 = A2
A1 + A2
3 B + 3 L = 120
B + L = 120 ÷ 3 = 40 cm
Perimeter of the field
= 2 (B + L)
= 2 x 40
= 80 cm
(b)
Circumference of the semicircle
=
227 x 7 x
12 = 11 cm
Perimeter of the remaining field
= 80 + 11 - 7
= 84 cm
Answer(s): (a) 80 cm; (b) 84 cm