A toy manufacturer needs a piece of plastic in the shape of a right triangle with the longer leg 4 cm more than the shorter leg and the hypotenuse 8 cm more than the shorter leg. How long should the sides of the triangle be?
The sides are __, ___, __
Let the shorter leg=L
The longer leg =L+4
The Hypotenuse=L+8
[L+8]^2 =L^2 +[L+4]^2 By Pythagoras's Theorem
Solve for L:
(L + 8)^2 = L^2 + (L + 4)^2
Expand out terms of the right hand side:
(L + 8)^2 = 2 L^2 + 8 L + 16
Subtract 2 L^2 + 8 L + 16 from both sides:
-16 - 8 L - 2 L^2 + (L + 8)^2 = 0
Expand out terms of the left hand side:
-L^2 + 8 L + 48 = 0
The left hand side factors into a product with three terms:
-((L - 12) (L + 4)) = 0
Multiply both sides by -1:
(L - 12) (L + 4) = 0
Split into two equations:
L - 12 = 0 or L + 4 = 0
Add 12 to both sides:
L = 12 or L + 4 = 0
Subtract 4 from both sides:
L = 12 or L = -4 (Since this is negative, discard it)
So, Legs of the triangle are: Shortest =12 cm, Longest=12+4=16 cm, Hypotenuse=12+8=20 cm
Let the shorter leg=L
The longer leg =L+4
The Hypotenuse=L+8
[L+8]^2 =L^2 +[L+4]^2 By Pythagoras's Theorem
Solve for L:
(L + 8)^2 = L^2 + (L + 4)^2
Expand out terms of the right hand side:
(L + 8)^2 = 2 L^2 + 8 L + 16
Subtract 2 L^2 + 8 L + 16 from both sides:
-16 - 8 L - 2 L^2 + (L + 8)^2 = 0
Expand out terms of the left hand side:
-L^2 + 8 L + 48 = 0
The left hand side factors into a product with three terms:
-((L - 12) (L + 4)) = 0
Multiply both sides by -1:
(L - 12) (L + 4) = 0
Split into two equations:
L - 12 = 0 or L + 4 = 0
Add 12 to both sides:
L = 12 or L + 4 = 0
Subtract 4 from both sides:
L = 12 or L = -4 (Since this is negative, discard it)
So, Legs of the triangle are: Shortest =12 cm, Longest=12+4=16 cm, Hypotenuse=12+8=20 cm