A triangle has side lengths measuring [tex]\(3x \, \text{cm}\)[/tex], [tex]\(7x \, \text{cm}\)[/tex], and [tex]\(h \, \text{cm}\)[/tex]. Which expression describes the possible values of [tex]\(h\)[/tex], in cm?

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



Answer :

To determine the possible values of [tex]\( h \)[/tex] for a triangle with side lengths [tex]\( 3x \, \text{cm} \)[/tex], [tex]\( 7x \, \text{cm} \)[/tex], and [tex]\( h \, \text{cm} \)[/tex], we can use the triangle inequality theorem. The theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the remaining side.

We need to check the three possible combinations:

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

Let’s simplify each inequality individually:

1. [tex]\( 3x + 7x > h \)[/tex]
[tex]\[ 10x > h \quad \text{or} \quad h < 10x \][/tex]

2. [tex]\( 3x + h > 7x \)[/tex]
[tex]\[ h > 7x - 3x \quad \text{or} \quad h > 4x \][/tex]

3. [tex]\( 7x + h > 3x \)[/tex]
[tex]\[ h > 3x - 7x \quad \text{or} \quad h > -4x \][/tex]
Since [tex]\( h \)[/tex] and [tex]\( x \)[/tex] both represent positive lengths, [tex]\( h > -4x \)[/tex] is always true and does not provide additional constraints.

Combining the simplified inequalities from (1) and (2), we get:
[tex]\[ 4x < h < 10x \][/tex]

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