4 identical triangles are cut off from the 4 corners of a square of side 20cm as shown . by how much did the perimeter decrease.

Perimeter of square = 4s
 = 4 * 20 
 = 80 cm
Reduced side of triangle = 4(4 + 3)
 = 4*7
 = 28
Increased side of triangle = 4 * 4 + 3 * 3
 = 16 + 9
 = under root 25
 = 5 cm
5 * 4 = 20  cm
28-20 = 8 cm
Therefore, the perimeter decreased by 8 cm.
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The perimeter of the original square is 4× s=80 cm. To find the side of the small cut triangle, we must use Pythagoras Theorem. 32+42=hypotenuse 2. The hypotenuse will be √9+16 = √25= 5cm. Now the decrease in perimeter will be 80- (14+5+5+12+5+5+14+12)=80-72 cm= 8cm.
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The perimeter of the original square is 4× s=80 cm. To find the side of the small cut triangle, we must use Pythagoras Theorem. 32+42=hypotenuse 2. The hypotenuse will be √9+16 = √25= 5cm. Now the decrease in perimeter will be 80- (14+5+5+12+5+5+14+12)=80-72 cm= 8cm.
 
  • -2
Dalbir has to carve a right circular cylinder of the maximum possible volume from the below wooden cuboid shown in the image. What would be the volume (in cm3) of the cylinder?
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