If side of cube is decreased by 25 percent find percent area decreased
Answers
Answer:
262.5%
Step-by-step explanation:
Let side of cube be x unit
ATQ , side is decreased by 25%
old side
decrease in side = --------------- × 25
100
Old side =x ,and 25 cut 100 four times
x
Decrease in side= --------
4
New side = x - (x/4)
=3x/4 unit
Original surface area= 6(original side)²
=6(x)²
=6x² square unit
New surface area= 6(new side)²
=6( 3x/4)²
=6 (9x² /16)
=(27/8)x² square unit
Decrease in surface area=old surface
area - new surface area
=6x² - (27/8) x²
={6 -(27/8)} x²
={(48-27)/8} x²
=(21/8) x² square unit
decrease in S.A.
% decrease in S.A.=-------------------- ×100
old S.A.
(21/8) x²
= ------------------ ×100
x²
x² cancel out from numerator and denominator and on solving further we get
% Decrease in surface area =262.5%
Answer:
Step-by-step explanation:
Given that Each side of cube is decreased by 25%.
Percentage decrease in surface area:
= [x + y + xy/100]%
= [-25 + -25 + (-25)(-25)/100]%
= [-50 + 625/100]%
= [-50 + 6.25]%
= -43.75%.