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What is the area of a triangle whose sides measure 15 inches, 18 inches, and 21 inches?

Give your answer in simplified radical form.

 May 1, 2020
 #1
avatar+27001 
+3

FIrst      is it a right triangle ?      15^2 + 18^2  = 21^2         No it is not

 

Try using Heron's Formula   

 May 1, 2020
 #3
avatar+88 
0

You may also be able to use Pythagoras Theorem (SSS) to find x.y and then convert x.y into radical form x a/b

 

x = whole number

y = .decimal

a/b = fraction from y

MathsLlama  May 1, 2020
 #4
avatar+88 
0

Haha

Human minds think alike 

MathsLlama  May 1, 2020
 #1
avatar+88 
0

Area=√p(p−a)(p−b)(p−c)

Where p is half the perimeter = a+b+c/2

 

This is the formula for finding the area of a triangle with 3 different sides (called Heron's Formula), but unfortunately, I can't help you when it comes to simplified radical form as I do not know how to calculate that.

MathsLlama May 1, 2020
 #3
avatar+88 
0

You may also be able to use Pythagoras Theorem (SSS) to find x.y and then convert x.y into radical form x a/b

 

x = whole number

y = .decimal

a/b = fraction from y

MathsLlama  May 1, 2020
 #4
avatar+88 
0

Haha

Human minds think alike 

MathsLlama  May 1, 2020
 #5
avatar+111456 
+1

s =  [ 15 + 18 + 21] / 2   =  54 / 2  =  27

 

Area =  √ [ 27  (27 - 15) (27 - 18) ( 27 - 21 ) ]  =

 

√[ 27 * 12 * 9 * 6 ] =

 

√ 27  * √12 * √9 * √6  =

 

3√3 * 2√3  * 3 * √6  =

 

18 * √3 * √3 * √6  =

 

18 * 3 * √6  =

 

54√6

 

 

cool cool cool

 May 1, 2020

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