Question

Find the percentage decrease in the area of a triangle if each of its side is halved.

Answer 1

Answer:

Area of triangle = A = square root of [s(s-a)(s-b)(s-c) where 2s =a+b+c.

Each side is halved,

s’ = s/2

(s’-a’) = (s-a)/2.

s’-b’) = (s-b)/2.

s’-c’) = (s-c)/2.

New areaA’ = square root of [s(s-a)(s-b)(s-c) /16. = A/ 4.

Change in area = 3/4 A= 75% decrease

Step-by-step explanation:

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Answer 2

Answer:

75%

Step-by-step explanation:

Let original size of:

b = x cm

h = y cm

A = 1/2 * b * h = xy/2

Let new size of:

b' = x/2 cm

h' = y/2 cm

A' = 1/2 * b' * h' = 1/2 * x/2 * y/2

= xy/8

Percentage change:

(A' - A)/A * 100

= (xy/2 - xy/8)/xy/2 * 100

= (-3xy/8)/(xy/2) *100

= -3xy/8 * 2/xy * 100

= -3/4 * 100

= -75%

'-' represents that there is a decrease in area.

But in the question it is asked decrease so the answer = 75%