BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Area of the Triangle / Coordinate Geometry

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 2663
Joined: Wed Jan 14, 2015 8:25 am
Location: Boston, MA
Thanked: 1153 times
Followed by:128 members
GMAT Score:770

by DavidG@VeritasPrep » Sun Mar 06, 2016 9:02 am
sukhman wrote:what is the area of a triangle whose vertices are the points (0,0),(1,3) and (3,3)?
A) 4.5 B)3.5 C)3 D)2.75 E)2
Remember that the base and the height must form a 90 degree angle. If the base is the distance from 1,3 to 3,3, then BASE = 3-1 = 2. The height can be the distance from the 3,3 to the x axis, which would be 3. Height = 3-0 = 3. (remember the height doesn't have to be a side within the triangle; it just needs to be perpendicular to the base.)

If the Base = 2 and the Height = 3, then B*H/2 = 2*3/2 = 3.

See the figure below:


Image
Veritas Prep | GMAT Instructor

Veritas Prep Reviews
Save $100 off any live Veritas Prep GMAT Course
Top
GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pm
Location: East Bay all the way
Thanked: 625 times
Followed by:119 members
GMAT Score:780

by Matt@VeritasPrep » Thu Mar 17, 2016 8:52 pm
You could also find the area of the rectangle around the triangle, then subtract the two right triangles that you don't want:

Area of rectangle = 3 * 3

Area of right triangle on top = (1 * 3)/2

Area of right triangle on bottom = (3 * 3)/2

From here, (Rectangle - first ∆ - second ∆) = 9 - 1.5 - 4.5 = 3

So we're left with the triangle we want, which has an area of 3.
Top
Post new topic Post Reply
• Page 1 of 1