Basic Geometry : 45/45/90 Right Isosceles Triangles

Study concepts, example questions & explanations for Basic Geometry

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Example Questions

Example Question #101 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the diameter of the circle is .

Possible Answers:

Correct answer:

Explanation:

1

Notice that the given triangle is a right isosceles triangle. The hypotenuse of the triangle is the same as the diameter of the circle; therefore, we can use the Pythagorean theorem to find the length of the legs of this triangle.

Substitute in the given hypotenuse to find the length of the leg of a triangle.

Simplify.

Now, recall how to find the area of a triangle.

Since we have a right isosceles triangle, the base and the height are the same length.

Solve.

Example Question #102 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the diameter of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

Notice that the given triangle is a right isosceles triangle. The hypotenuse of the triangle is the same as the diameter of the circle; therefore, we can use the Pythagorean theorem to find the length of the legs of this triangle.

Substitute in the given hypotenuse to find the length of the leg of a triangle.

Simplify.

Now, recall how to find the area of a triangle.

Since we have a right isosceles triangle, the base and the height are the same length.

Solve.

Example Question #103 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the diameter of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

Notice that the given triangle is a right isosceles triangle. The hypotenuse of the triangle is the same as the diameter of the circle; therefore, we can use the Pythagorean theorem to find the length of the legs of this triangle.

Substitute in the given hypotenuse to find the length of the leg of a triangle.

Simplify.

Now, recall how to find the area of a triangle.

Since we have a right isosceles triangle, the base and the height are the same length.

Solve.

Example Question #104 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

Example Question #105 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is 

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

Example Question #106 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

 

Example Question #107 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

Example Question #108 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

Example Question #109 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

 

Example Question #110 : 45/45/90 Right Isosceles Triangles

Find the area of the triangle if the radius of the circle is .

1

Possible Answers:

Correct answer:

Explanation:

1

The two tick marks on the image indicate that those sides are congruent; therefore, this is an isosceles right triangle.

Notice that the hypotenuse of the triangle is also the diameter of the circle. Recall the relationship between the diameter of a circle and its radius:

Substitute in the value of the radius to find the length of the diameter.

Simplify.

Now, use the Pythagorean theorem to find the lengths of the missing sides of the triangle.

Now, recall how to find the area of a triangle:

In this case, because we have an isosceles right triangle,

Take the equation derived from the Pythagorean theorem and plug it in to the equation above.

Simplify.

Now, substitute in the value of the hypotenuse to find the area of the triangle.

Solve.

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