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February 6th, 2019, 04:53 PM  #1 
Member Joined: Jan 2019 From: tornto Posts: 48 Thanks: 0  triangle?
Could not solve this on my exam. Please help with explanation. Thanks. Find the value of x which makes the area of this triangle equal 72. A. x=10.5 B. x=6 C. x=4.6875 D. x=9.375 triangle Last edited by skipjack; February 6th, 2019 at 08:28 PM. 
February 6th, 2019, 06:38 PM  #2 
Newbie Joined: Jan 2019 From: Arrakis Posts: 7 Thanks: 0 
A=(1/2)(b)(h) 72=(1/2)(8)(h) [do keep in mind that h=(2x3)] 72=(4)(h) 18=h Therefore, if h=18 and h=(2x3) then 18=2x3 18=2x3 21=2x 10.5=x Final answer: A 
February 6th, 2019, 08:43 PM  #3 
Global Moderator Joined: Dec 2006 Posts: 20,942 Thanks: 2210 
The triangle can be thought of as the lower left half of a rectangle (with area 72 × 2 = 144). The height of that rectangle (and also the triangle) is therefore 144/8 = 18. Hence 2x  3 = 18, which implies that x = 10.5 (answer A). I've no idea how anyone could arrive at answer C or D. 

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