Answer: 50
Step-by-step explanation:
Answer:
Multiply all lengths by 150÷100=1.5
New value of AB = 1.5 × 20cm=30cm
New value of AC = 1.5 ×21cm= 31.5cm
New value of BC = 1.5 ×9cm= 13.5cm
New perimeter of ∆A'B'C= 13.5cm +31.5cm +30cm= 75cm.
