High School Math : Triangles

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #19 : How To Find The Length Of The Side Of A Right Triangle

Given a right triangle, solve for the missing leg if one leg is 12 and the hypotenuse is 13.

Possible Answers:

Correct answer:

Explanation:

Since the traingle is a right traingle, we can use the Pythagorean Theorem to solve for the missing leg:

 and the hypotenuse

Example Question #21 : How To Find The Length Of The Side Of A Right Triangle

Triangles

Points \dpi{100} \small A, \dpi{100} \small B, and \dpi{100} \small C are collinear (they lie along the same line). , ,

Find the length of segment \overline{BD}.

Possible Answers:

\frac{2\sqrt{3}}{3}

2\sqrt{3}

2

\frac{\sqrt{3}}{2}

\frac{4\sqrt{3}}{3}

Correct answer:

\frac{4\sqrt{3}}{3}

Explanation:

The length of segment \overline{BD} is \frac{4\sqrt{3}}{3}

Note that triangles \dpi{100} \small ACD and \dpi{100} \small BCD are both special, 30-60-90 right triangles. Looking specifically at triangle \dpi{100} \small ACD, because we know that segment \overline{AD} has a length of 4, we can determine that the length of segment \overline{CD} is 2 using what we know about special right triangles. Then, looking at triangle \dpi{100} \small BCD now, we can use the same rules to determine that segment \overline{BD} has a length of \frac{4}{\sqrt{3}}

which simplifies to \frac{4\sqrt{3}}{3}.

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Possible Answers:

Correct answer:

Explanation:

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Rt_triangle_letters

If angle  and , what is the value of ?

Possible Answers:

Correct answer:

Explanation:

Once we see that , we know that we're working with a right triangle and that  will be the hypotenuse.

At this point we can use the Pythaogrean theorem () or, in this case: .

Plug in our given values to solve:

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Rt_triangle_letters

If angle  and , what is the value of ?

Possible Answers:

Correct answer:

Explanation:

Once we see that , we know we're working with a right triangle and that  will be the hypotenuse.

At this point we can use the Pythaogrean theorem () or, in this case: .

Plug in our given values to solve:

Subtract  from both sides:

Example Question #4 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

A right triangle has legs of  and . What is the hypotenuse?

Possible Answers:

Correct answer:

Explanation:

To solve this problem, use the Pythagorean theorem: the sum of the square of the legs equals the square of the hyoptenuse or, mathematically, .

Plug in our given values.

 is not a perfect square, but let's see if we can find a factor that is a perfect square.

 IS a perfect square, so we can simplify!

This is going to be true of all isoceles right triangles: the pattern will always be .

Example Question #2 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

A right triangle has legs of  and . What is the hypotenuse?

Possible Answers:

Correct answer:

Explanation:

To solve this problem, use the Pythagorean theorem: the sum of the square of the legs equals the square of the hyoptenuse or, mathematically, .

Plug in our given values.

is not a perfect square, but let's see if we can find a factor that is a perfect square.

IS a perfect square, so we can simplify!

Example Question #3 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Solve for :

Question_12

Possible Answers:

Correct answer:

Explanation:

Solve for  using the Pythagorean Theorem:

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Trig_id

If  and , how long is side ?

Possible Answers:

Not enough information to solve

Correct answer:

Explanation:

This problem is solved using the Pythagorean theorem  .  In this formula  and  are the legs of the right triangle while  is the hypotenuse.

Using the labels of our triangle we have:

 

 

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

If one of the short sides of a 45-45-90 triangle equals 5, how long is the hypotenuse?

Possible Answers:

√15

π

√10

5

5√2

Correct answer:

5√2

Explanation:

Using the Pythagorean theorem, x2 + y2 = h2. And since it is a 45-45-90 triangle the two short sides are equal. Therefore 52 + 52 = h2 .  Multiplied out 25 + 25 = h2.

Therefore h2 = 50, so h = √50 = √2 * √25 or 5√2.

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