The three sides of an equilateral triangle are increased by 20 cm, 30 cm, and 40 cm, respectively. The perimeter of the resulting triangle is between twice and three times the perimeter of the original triangle. What can you conclude about the length of a side of the original triangle? It is between: a- 10 cm and 30 cm b- 15 cm and 30 cm c- 7.5 cm and 10 cm d- 15 cm and 45 cm

Question

The three sides of an equilateral triangle are increased by 20 cm, 30 cm, and 40 cm, respectively.  The perimeter of the resulting triangle is between twice and three times the perimeter of the original triangle.  What can you conclude about the length of a side of the original triangle?  It is between: a- 10 cm and 30 cm b- 15 cm and 30 cm c- 7.5 cm and 10 cm d- 15 cm and 45 cm

anonymous · Answer

now let the sides be   a,b,c 


now the new perimeter is 

a +b+c+90

old perimeter a+b+c

2a +2b + 2c < a + b +c +90<3a+3b+3c

a + b +c < 90 < 2(a + b +C )