Question

Which of the following triangles have a perimeter of 24 cm?

• A. An equilateral triangle with side 8 cm
• B. A scalene triangle with sides 11 cm, 6cm and 7 cm
• C. A scalene triangle with sides 9 cm, 10 cm and 4cm
• D. An isosceles triangle with base 10 cm and one of the equal sides 7 cm

Answer 1

Answer: (A), (B), (D)

The correct options are
A An equilateral triangle with side 8 cm
B A scalene triangle with sides 11 cm, 6cm and 7 cm
D An isosceles triangle with base 10 cm and one of the equal sides 7 cm

(1) Perimeter of an equilateral triangle
= $3\times sidelength$ = $3\times 8=24cm$

(2) Perimeter of a scalene triangle
= 11 + 6 + 7 = $24cm$

(3) Perimeter of a scalene triangle
= 9 + 10 + 4 = $23cm\ne 24cm$

(4) Perimeter of an isosceles triangle
= 10 + 7 + 7 = $24cm$