Math Problem Statement

The perimeter of a right triangle is 60 cm and its hypotenuse is 25 cm. Find the area of the triangle.

Solution

Given the problem:

  • The perimeter of a right triangle is 60cm60 \, \text{cm}.
  • The hypotenuse is 25cm25 \, \text{cm}.

We need to find the area of the triangle.

Let's denote the sides of the right triangle as aa, bb (the legs), and cc (the hypotenuse). From the problem, we have:

  1. c=25cmc = 25 \, \text{cm}
  2. The perimeter a+b+c=60cma + b + c = 60 \, \text{cm}

Substitute cc into the perimeter equation: a+b+25=60a + b + 25 = 60 a+b=35(Equation 1)a + b = 35 \quad \text{(Equation 1)}

Since it's a right triangle, we also have: a2+b2=c2a^2 + b^2 = c^2 a2+b2=252a^2 + b^2 = 25^2 a2+b2=625(Equation 2)a^2 + b^2 = 625 \quad \text{(Equation 2)}

To solve for aa and bb, we can express bb in terms of aa using Equation 1: b=35ab = 35 - a

Substitute into Equation 2: a2+(35a)2=625a^2 + (35 - a)^2 = 625

Expanding this: a2+(3522×35×a+a2)=625a^2 + (35^2 - 2 \times 35 \times a + a^2) = 625 a2+122570a+a2=625a^2 + 1225 - 70a + a^2 = 625 2a270a+1225=6252a^2 - 70a + 1225 = 625

Combine like terms: 2a270a+600=02a^2 - 70a + 600 = 0

Divide by 2 to simplify: a235a+300=0a^2 - 35a + 300 = 0

This is a quadratic equation. We can solve for aa using the quadratic formula: a=b±b24ac2aa = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Where a=1a = 1, b=35b = -35, and c=300c = 300: a=35±(35)24×1×3002×1a = \frac{35 \pm \sqrt{(-35)^2 - 4 \times 1 \times 300}}{2 \times 1} a=35±122512002a = \frac{35 \pm \sqrt{1225 - 1200}}{2} a=35±252a = \frac{35 \pm \sqrt{25}}{2} a=35±52a = \frac{35 \pm 5}{2}

So, a=402=20ora=302=15a = \frac{40}{2} = 20 \quad \text{or} \quad a = \frac{30}{2} = 15

If a=20a = 20: b=3520=15b = 35 - 20 = 15

If a=15a = 15: b=3515=20b = 35 - 15 = 20

Thus, the legs are a=15a = 15 and b=20b = 20 (or vice versa).

Now, let's find the area of the triangle: Area=12×a×b=12×15×20=150cm2\text{Area} = \frac{1}{2} \times a \times b = \frac{1}{2} \times 15 \times 20 = 150 \, \text{cm}^2

So, the area of the triangle is 150 cm².

Would you like further details or have any questions?

Here are some related questions:

  1. What are the other possible dimensions of a right triangle given a specific hypotenuse?
  2. How can we verify the Pythagorean theorem using the dimensions found?
  3. What happens to the area if we change the hypotenuse while keeping the perimeter constant?
  4. How does the triangle's shape change if the perimeter is increased while keeping the hypotenuse fixed?
  5. Can we derive the formula for the area of any right triangle using just its perimeter and hypotenuse?

Tip: Remember, for right triangles, the Pythagorean theorem a2+b2=c2a^2 + b^2 = c^2 is always a quick way to relate the sides if you know two of the three.

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Math Problem Analysis

Mathematical Concepts

Geometry
Right Triangles
Algebra

Formulas

Perimeter of a triangle: a + b + c
Pythagorean theorem: a^2 + b^2 = c^2
Quadratic formula: x = (-b ± √(b^2 - 4ac)) / 2a
Area of a triangle: (1/2) × base × height

Theorems

Pythagorean Theorem
Quadratic Formula

Suitable Grade Level

Grades 8-10