Answer:
See below.
Step-by-step explanation:
ABC is an isosceles triangle with BA = BC.
That makes angles A and C congruent.
ABD is an isosceles triangle with AB = AD.
That makes angles ABD and ADB congruent.
Since m<ABD = 72 deg, then m<ADB = 72 deg.
Angles ADB and CDB are a linear pair which makes them supplementary.
m<ADB + m<BDC = 180 deg
72 deg + m<BDC = 180 deg
m<CDB = 108 deg
In triangle ABD, the sum of the measures of the angles is 180 deg.
m<A + m<ADB + m<ABD = 180 deg
m<A + 72 deg + 72 deg = 180 deg
m<A = 36 deg
m<C = 36 deg
In triangle BCD, the sum of the measures of the angles is 180 deg.
m<CBD + m<C + m<BDC = 180 deg
m<CBD + 36 deg + 108 deg = 180 deg
m<CBD = 36 deg
In triangle CBD, angles C and CBD measure 36 deg making them congruent.
Opposite sides DB and DC are congruent making triangle BCD isosceles.
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
When using substitution, we are imputing an equation in place of a variable to eliminate one of the variables in the equation so that we can solve for the remaining variable.
For this example, we will be plugging in (-4y+12) wherever "x" is in the other equation.
3/4 x -5y = 7
3/4(-4y+12) -5y =7
((3/4)(-4y))+((3/4)12)-5y=7
-3y+9-5y=7
-8y= -2
y=(1/4)
Now find "x" by plugging in the y-value.
x=(-4*(1/4))+12
x= -1 +12
x=11
any questions? feel free to comment below!
Answer: 63
Step-by-step explanation: 21+21+21
