Answer:
10.8
Step-by-step explanation:
By sine rule:

Time taken by Ria to paint a room = 4 hours
Time taken by Destiny to paint a room = 6 hours
If they work together, they complete 1 job. So,

The LCD of 4 and 6 is 12




Hence, both of them can paint the room in
hours or 2.4 hours.
We know that
if <span>QT is an altitude of triangle QRS
then
</span><span>the measure of angle QTS is equal to 90</span>°
so
6x+36=90-----> 6x=90-36----> x=54/6
x=9
QR=2x-5-----> QR=2*9-5-----> QR=18-5-----> QR=13
the answer is
QR=13
X^2 = 7^2 + 24^2x^2 =49 + 576x^2 = 625
x = 25