Respuesta :

Answer:

The length of the altitude PM is 3.5 cm.

Step-by-step explanation:

We are given that QT and PM  are the altitudes of the triangle PQR. Also, QR = 8 cm, PR = 7 cm and  QT = 4 cm.

We have to find the length of the altitude PM.

As we know that the area of the triangle is given by;

Area of triangle =  [tex]\dfrac{1}{2} \times \text{Base} \times \text{Height(Altitude)}[/tex]

Here, in [tex]\triangle[/tex]PQR; Base = PR = 7 cm

Height(Altitude) = QT = 4 cm

So, the area of the triangle PQR =  [tex]\frac{1}{2} \times 7 \times 4[/tex]

                                                       =  14 sq cm.

Similarly, the area of the triangle can also be;

Area  =  [tex]\frac{1}{2} \times \text{QR} \times \text{PM}[/tex]

Here, QR = Base of triangle PQR = 8 cm

PM = the required altitude

So, Area of triangle  =  [tex]\frac{1}{2} \times 8\times \text{PM}[/tex]

              [tex]14 =4 \times \text{PM}[/tex]

             PM  =  [tex]\frac{14}{4}[/tex]  = 3.5 cm

Hence, the length of the altitude PM is 3.5 cm.