You have two 30-60-90 triangles, ADC and BDC.
The ratio of the lengths of the sides of a 30-60-90 triangle is
short leg : long leg : hypotenuse
1 : sqrt(3) : 2
Using triangle ADC, we can find length AC.
Using triangle BDC, we can find length BC.
Then AB = AC - BC
First, we find length AC.
Look at triangle ACD.
DC is the short leg opposite the 30-deg angle.
DC = 10sqrt(3)
AC = sqrt(3) * 10sqrt(3) = 3 * 10 = 30
Now, we find length BC.
Look at triangle BCD.
For triangle BCD, the long leg is DC and the short leg is BC.
BC = 10sqrt(3)/sqrt(3) = 10
AB = AC - BC = 30 - 10 = 20
3x + 2y = 39
-3x -3x
2y = 39-3x
— ———
2 2
y= 19.5 - 3x/2
plug (19.5 - 3x/2) for y
1.5x - 2(19.5 - 3x/2)= 39
x= 17.33333333334
Do 100÷8, then whatever the answer is multiply it by 8 and ta da
The motorists average speed was 58 kph
1) True
2)True
3)False
4)True
Hope this helps! :)
