Answer:
168 meters squared
Step-by-step explanation:
The area of the triangle is A= 1/2 b*h. Here this area is 21 meters squared. The sides of the triangle have been multiplied by 4. This means, if the base was b, it is now 4b. This also means, if the height was h, it is now 4h. So the area is A= 1/2 4b*4h = 1/2 (16bh) = 8bh.
So the area of the larger triangle will be 8 times bigger.
21*8 = 168
