Let x=ab=ac, and y=bc, and z=ad.
Since the perimeter of the triangle abc is 36, you have:
Perimeter of abc = 36
ab + ac + bc = 36
x + x + y = 36
(eq. 1) 2x + y = 36
The triangle is isosceles (it has two sides with equal length: ab and ac). The line perpendicular to the third side (bc) from the opposite vertex (a), divides that third side into two equal halves: the point d is the middle point of bc. This is a property of isosceles triangles, which is easily shown by similarity.
Hence, we have that bd = dc = bc/2 = y/2 (remember we called bc = y).
The perimeter of the triangle abd is 30:
Permiter of abd = 30
ab + bd + ad = 30
x + y/2 + z =30
(eq. 2) 2x + y + 2z = 60
So, we have two equations on x, y and z:
(eq.1) 2x + y = 36
(eq.2) 2x + y + 2z = 60
Substitute 2x + y by 36 from (eq.1) in (eq.2):
(eq.2') 36 + 2z = 60
And solve for z:
36 + 2z = 60 => 2z = 60 - 36 => 2z = 24 => z = 12
The measure of ad is 12.
If you prefer a less algebraic reasoning:
- The perimeter of abd is half the perimeter of abc plus the length of ad (since you have "cut" the triangle abc in two halves to obtain the triangle abd).
- Then, ad is the difference between the perimeter of abd and half the perimeter of abc:
ad = 30 - (36/2) = 30 - 18 = 12
1-.63=.37. so $0.63+$0.37=$1.00
Answer:
6
Step-by-step explanation:
4 = 12/3
12/3 divided by 2/3 = 6
2/3
2/3
2/3
2/3
2/3
2/3
+
______
12/3
The answer is 6
Answer:
6 quarters, 4 dimes, and 2 nickels
Answer:
Heptagon = 84 ft²
Octagon = 186 yd²
Triangle = 48√3 m²
Step-by-step explanation:
where:
= length of apothem
= perimeter
<u>Heptagon</u>
a = 5.0 ft
p = 33.6 ft
⇒ area = 1/2 x 5.0 x 33.6 = 84 ft²
<u>Octagon</u>
a = 7.5 yd
p = 8 x 6.2 = 49.6 yd
⇒ area = 1/2 x 7.5 x 49.6 = 186 yd²
<u>Triangle</u>
Formula for the apothem of an equilateral triangle :
where 
= side length
a = 4, so:
Now we know the side length, we can calculate the perimeter (p):
p = 3 x 8√3 = 24√3
⇒ area = 1/2 x 4 x 24√3 = 48√3 m²
