Equation :
[x(x+4)]/2=6 (as (b*h)/2=A)
x*x + 4*x -12 = 0
so, x = 2 units(as -6 is negative)
Grandpa's age is 75 years
Seven times the age of junior = age of grandpa + 9 jears = 75 + 9 = 84 years
Hence, the age of junior will be 84 / 7 = 12 years. (Since 84 is seven times his age, you have to devide by seven).
--> Junior is 12 years old.
I hope I've been helpful, MarkV
For the right triangle to be given in name of three letters such as this, the right angle is most likely to be in the center, in this case letter K. To determine the common trigonometric properties of a certain angle we may use of the mnemonics SOH - CAH - TOA.
sin angle = opposite side / hypotenuse
cosine angle = adjacent side / hypotenuse
tangent angle = opposite side / adjacent side
If we let small letter j, k, and l be the sides opposite to angles J, K, and L, respectively. Then, the cos (L) will be,
cos (L) = j/k
Let,
the no. of adults be "x"
then, the no. of childern = total people - total adults
= (30 - x)
Now,
According to the quesiton,
2 (30 - x) + 5x = 87
60 - 2x + 5x = 87
60 + 3x = 87
3x = 87 - 60
3x = 27
x = 27 / 3
x = 9
So, there were 9 adults in the group
