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Triangle MRN is created when an equilateral triangle is folded in half.

Triangle N R M is shown. Angle N R M is a right angle. An altitude is drawn from point R to point S on side M N to form a right angle. The length of N S is 6, the length of S M is 2, the length of R M is x, the length of N R is y, and the length of R S is z.

What is the value of y?

2√3 units
4 units
4√3 units
8 units

User Bluemalkin
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1 Answer

0 votes

The value of y is: 4 units

What is the length of the triangle?

The given information:

NR is perpendicular to MN

NS = 6 units

SM = 2 units

RM = x units

NR = y units

RS = z units

Use the Pythagorean theorem on right triangle NRS:

y² = RS² + NS²

y² = z² + 6²

Use the Pythagorean theorem on right triangle RMS:

x² = RS²+ SM²

x² = z² + 2² ___________(1)

Since NR is the hypotenuse of both right triangles NRS and RMS, we can set the two expressions for z² equal to each other:

y² = x² ___________(2)

Substitute the expression for x² in equation 1:

y² = z² + 2²

Solve for y:

y = √(z² + 2²)

Since MRN is half of an equilateral triangle, we know that MN = 2x:

MN = 2x

Use the Pythagorean theorem on right triangle MNR:

y² = RM² + (MN/2)²

y² = x² + (x)²

y² = 2x²

Set the two expressions for y² equal to each other:

y² = y²

z² + 2² = 2x²

Substitute the expression for x² from equation 1:

z² + 2² = 2(z²+ 2²)

Simplify and solve for z²:

z² + 2² = 2z² + 4²

-z² = 4² - 2²

z² = 12

Solve for z:

z = √12

z = 2√3

Substitute the value of z back into the equation

y = √(z² + 2²)

y = √(2√3)² + 2²

y = √(12 + 4)

y = √16

y = 4

From equation 2 we can say that

y = x

Hence,

y = x = 4 units

Option B is the right choice.

Triangle MRN is created when an equilateral triangle is folded in half. Triangle N-example-1
User Juliean
by
7.2k points