A triangle has side lengths measuring [tex]$3x$ cm, [tex]$7x$[/tex] cm[/tex], and [tex]$h$ cm[/tex]. Which expression describes the possible values of [tex]$h$[/tex] in cm?

[tex]
A. h = 4x \\
B. 4x \ \textless \ h \ \textless \ 10x \\
C. h = 10x \\
D. 10x \ \textless \ h \ \textless \ 4x
[/tex]



Answer :

To determine the possible values of [tex]\( h \)[/tex] that would make a valid triangle with the given side lengths [tex]\( 3x \)[/tex] cm, [tex]\( 7x \)[/tex] cm, and [tex]\( h \)[/tex] cm, we need to apply the triangle inequality theorem. The triangle inequality theorem states that for any triangle with sides [tex]\( a \)[/tex], [tex]\( b \)[/tex], and [tex]\( c \)[/tex]:

1. [tex]\( a + b > c \)[/tex]
2. [tex]\( a + c > b \)[/tex]
3. [tex]\( b + c > a \)[/tex]

Here, the sides of the triangle are [tex]\( 3x \)[/tex], [tex]\( 7x \)[/tex], and [tex]\( h \)[/tex]. Let's apply the triangle inequality theorem to these sides:

1. [tex]\( 3x + 7x > h \)[/tex]
[tex]\[ 10x > h \][/tex]

2. [tex]\( 3x + h > 7x \)[/tex]
[tex]\[ h > 4x \][/tex]

3. [tex]\( 7x + h > 3x \)[/tex]
[tex]\[ h > -4x \quad (\text{This inequality is not relevant as it will always be satisfied for positive \( x \)}) \][/tex]

Combining the valid inequalities from above, we get:
[tex]\[ 4x < h < 10x \][/tex]

So, the expression that describes the possible values of [tex]\( h \)[/tex] in cm is:
[tex]\[ 4x < h < 10x \][/tex]