All ACT Math Resources
Example Questions
Example Question #73 : Right Triangles
The lengths of the sides of a right triangle are consecutive integers, and the length of the shortest side is . Which of the following expressions could be used to solve for ?
Since the lengths of the sides are consecutive integers and the shortest side is , the three sides are , , and .
We then use the Pythagorean Theorem:
Example Question #71 : Triangles
Square is on the coordinate plane, and each side of the square is parallel to either the -axis or -axis. Point has coordinates and point has the coordinates .
Quantity A:
Quantity B: The distance between points and
The relationship cannot be determined from the information provided.
Quantity B is greater.
Quantity A is greater.
The two quantities are equal.
The two quantities are equal.
To find the distance between points and , split the square into two 45-45-90 triangles and find the hypotenuse. The side ratio of the 45-45-90 triangle is , so if the sides have a length of 5, the hypotenuse must be .
Example Question #124 : Geometry
What is the diagonal of a computer screen that measures inches tall by inches wide?
Plug the values into the Pythagorean Theorem
,
because we are solving for the diagonal we are looking for .
.
.
Example Question #131 : Geometry
A right triangle has legs of length and , what is the length of the hypotenuse?
To find the hypotenuse of a right triangle, use the Pythagorean Theorem and plug the leg values in for and :
Example Question #51 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem
A right triangle has a base of six and a height of eight. Using this information find the hypotenuse.
This question calls for us to use the Pythagorean Theorem. This theorem has a formula of
where a and b are the sides of a right triangle, adjacent to the right angle, and c is the hypotenuse.
Given our information
.
Example Question #52 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem
A right triangle has a base of seven and a height of twelve. Using this information find the hypotenuse.
This question calls for us to use the Pythagorean Theorem. This theorem has a formula of
where a and b are the sides of a right triangle, adjacent to the right angle, and c is the hypotenuse.
Given our information
.
Example Question #132 : Geometry
Marcus Absent is marking out some lines for a large canvas tent. He paces out to the north, places a peg, then turns east and paces another to place another peg. Stopping, he realizes he has forgotten the other pegs, so he makes a beeline for his original starting point.
How many does Marcus travel to get back to the pegs?
The Pythagorean Theorem states that for any right triangle with legs and and hypotenuse :
.
Applying this to Marcus's steps, we know that .
Expand:
So, . To find , just take the square root:
So, Marcus travels exactly back to the start.
Example Question #513 : Geometry
Justin travels to the east and to the north. How far away from his starting point is he now?
This is solving for the hypotenuse of a triangle. Using the Pythagorean Theorem, which says that
Example Question #52 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem
Susie walks north from her house to a park that is 30 meters away. Once she arrives at the park, she turns and walks west for 80 meters to a bench to feed some pigeons. She then walks north for another 30 meters to a concession stand. If Susie returns home in a straight line from the concession stand, how far will she walk from the concession stand to her house, in meters?
100
50
200
70
25
100
Susie walks 30 meters north, then 80 meters west, then 30 meters north again. Thus, she walks 60 meters north and 80 meters west. These two directions are 90 degrees away from one another.
At this point, construct a right triangle with one leg that measures 60 meters and a second leg that is 80 meters.
You can save time by using the 3:4:5 common triangle. 60 and 80 are and , respectively, making the hypotenuse equal to .
We can solve for the length of the missing hypotenuse by applying the Pythagorean theorem:
Substitute the following known values into the formula and solve for the missing hypotenuse: side .
Susie will walk 100 meters to reach her house.
Example Question #72 : Triangles
The lengths of the sides of a triangle are consecutive odd numbers and the triangle's perimeter is 57 centimeters. What is the length, in centimeters, of its longest side?
19
17
25
21
23
21
First, define the sides of the triangle. Because the side lengths are consecutive odd numbers, if we define the shortest side will be as , the next side will be defined as , and the longest side will be defined as . We can then find the perimeter of a triangle using the following formula:
Substitute in the known values and variables.
Subtract 6 from both sides of the equation.
Divide both sides of the equation by 3.
Solve.
This is not the answer; we need to find the length of the longest side, or .
Substitute in the calculated value for and solve.
The longest side of the triangle is 21 centimeters long.
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