In the diagram below, A C ≅ C E , and D is the midpoint of CE. If CE = 10x+18, DE = 7x-1, and BC = 9x+2, find AB.
Answer:
AB = 21
Step-by-step explanation:
Given:
AC = CE, with D as midpoint of CE,
CE = 10x + 18,
DE = 7x - 1,
BC = 9x + 2
Required:
Length of segment AB
SOLUTION:
Create an equation to enable you solve for the value of x
Since point D is the midpoint of CE, ½ of CE = DE.
Thus, we have the following equation:
½(10x + 18) = 7x - 1
Solve for x
Multiply both sides by 2
10x + 18 = (7x - 1)2
10x + 18 = 14x - 2
10x - 14x = -18 - 2
-4x = -20
Divide both sides by -4
x = 5
Find the numerical value of CE:
CE = 10x + 18
Plug in the value of x
CE = 10(5) + 18 = 50 + 18 = 68
Since AC = CE, therefore
AC = 68
BC = 9x + 2 = 9(5) + 2 = 45 + 2 = 47
AB + BC = AC
AB + 47 = 68 (substitution)
Subtract 47 from both sides
AB = 68 - 47
AB = 21
D is the midpoint of CE, so if you draw a line with those three points, it'll look like C-D-E.
Since DE = 7x-1, which also means CD = 7x-1.
CD + DE = CE, so (7x-1)+(7x-1) = 10x+18.
Therefore, x = 5 and CE = 68.
Since AC is congruent to CE, AC = 68.
Assuming the point B is somewhere between AC.
Since BC = 9x-2 and x = 5, which means BC = 43.
AC - BC = AB, so 68 - 43 = 25.
Therefore, AB = 25