Question

CLASSIFY THE TRIANGLES WHOSE SIDES MEASURE:

A. a = 15cm, b = 20cm and c = 25cm

B. a = 3cm, b = 3cm and c = 1cm

Answer 1

Triangle A is a scalene triangle.

Triangle B is an isosceles triangle

Exaplanation for the 1st Answer:

A scalene triangle is a triangle whose all side lengths are different.

Triangle A has the side lengths are 15, 20, 25. All these lengths are different, so this is a scalene triangle.

Explanation for the 2nd Answer:

An isosceles triangle has 2 sides lengths the same and the other side length different. Triangle B has side lengths of 3, 3, 1. Two side lengths are same, but 1 side length is different. So, this is an isosceles triangle.

Answer 2

Problem 1

a^2+b^2 = 25^2+20^2 = 225+400 = 625

c^2 = 25^2 = 625

We get the same output of 625.

This shows that a^2+b^2 = c^2 is true for (a,b,c) = (15,20,25). We have a pythagorean triple and this is a right triangle. This is also scalene as all three sides are different lengths.

Answer: Right scalene triangle

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Problem 2

a^2+b^2 = 3^2+3^2 = 18

while c^2 = 1^2 = 1

So a^2+b^2 = c^2 is not a true equation for this a,b,c set of values. We do not have a right triangle. Instead we have an acute triangle based on these rules below

• If a^2+b^2 = c^2, then we have a right triangle
• If a^2+b^2 > c^2, then we have an acute triangle
• If a^2+b^2 < c^2, then we have an obtuse triangle

We see that we have the form a^2+b^2 > c^2 since 18 > 1.

This acute triangle is also isosceles because a = b.

Answer: Isosceles acute triangle