# Area of scaled down triangle

• July 4th 2010, 06:59 AM
haftakhan
Area of scaled down triangle
ABC is a triangle with height of 4 cm and base of 7 cm,drawn to a scale of 1cm:3km. Find the actual area of the triangle.

How to solve such questions ?
• July 4th 2010, 07:15 AM
skeeter
Quote:

Originally Posted by haftakhan
ABC is a triangle with height of 4 cm and base of 7 cm,drawn to a scale of 1cm:3km. Find the actual area of the triangle.

How to solve such questions ?

area of a triangle is $A = \frac{1}{2} bh$

if the length scale is $a:b$ , then the area scale is $a^2:b^2$
• July 4th 2010, 08:03 AM
haftakhan
A=1/2*(4*3)(7*3)
A=126km square

Right ?
• July 4th 2010, 08:36 AM
Unknown008
Right! (Happy)
• July 4th 2010, 11:58 AM
HallsofIvy
Quote:

Originally Posted by haftakhan
A=1/2*(4*3)(7*3)
A=126km square

Right ?

Yes, that is correct.(Clapping) Skeeters point was this: A triangle with height 4 cm and base 7 cm has area (1/2)(4)(7)= 2(7)= 14 square cm. Since the scale is "1 cm to 3 km", and area is "length squared", that becomes 9*14 square km= 126 square km. Of course, the way you didn't is perfectly correct (and better than following someone else's method).