Answer: AB = 12.5, BC = 15
Step-by-step explanation:
Perimeter of ΔBCD = BC + CD + BD. Since it is an isoceles triangle, then BC = CD = BD. So, Perimeter of ΔBCD = 3BC
3BC = 45
÷3 ÷3
BC = 15
Perimeter of ΔABC = AB + BC + AC. Since it is an isosceles triangle with BC as the base, then AB = AC. So, Perimeter of ΔABC = 2AB + BC
2AB + BC = 40
2AB + 15 = 40
-15 -15
2AB = 25
÷2 ÷2
AB = 12.5
