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Right Triangles Calculator

Right Triangle Calculator

a =
b =
c =
P =
s =
K =
ha =
hb =
hc =

Right Triangle Shape

A = angle A
a = side a
B = angle B
b = side b
C = angle C
c = side c

K = area
P = perimeter

See Diagram Below:
ha = altitude of a
hb = altitude of b
hc = altitude of c

*Length units are for your reference only since the value of the resulting lengths will always be the same no matter what the units are.

Calculator Use

A right triangle is a special case of a triangle where 1 angle is equal to 90 degrees. In the case of a right triangle a2 + b2 = c2. This formula is known as the Pythagorean Theorem.

In our calculations for a right triangle we only consider 2 known sides to calculate the other 7 unknowns. For example, if we know a and b we can calculate c using the Pythagorean Theorem. c = √(a2 + b2). Once we know sides a, b, and c we can calculate the perimeter = P, the semiperimeter = s, the area = K, and the altitudes: ha, hb, and hc. Let us know if you have any other suggestions!

Formulas and Calculations for a right triangle:

• Pythagorean Theorem for Right Triangle: a2 + b2 = c2
• Perimeter of Right Triangle: P = a + b + c
• Semiperimeter of Right Triangle: s = (a + b + c) / 2
• Area of Right Triangle: K = (a * b) / 2
• Altitude a of Right Triangle: ha = b
• Altitude b of Right Triangle: hb = a
• Altitude c of Right Triangle: hc = (a * b) / c

1. Given sides a and b find side c and the perimeter, semiperimeter, area and altitudes

• a and b are known; find c, P, s, K, ha, hb, and hc
• c = √(a2 + b2)
• P = a + b + c
• s = (a + b + c) / 2
• K = (a * b) / 2
• ha = b
• hb = a
• hc = (a * b) / c

2. Given sides a and c find side b and the perimeter, semiperimeter, area and altitudes

• a and c are known; find b, P, s, K, ha, hb, and hc
• b = √(c2 - a2)
• P = a + b + c
• s = (a + b + c) / 2
• K = (a * b) / 2
• ha = b
• hb = a
• hc = (a * b) / c

Weisstein, Eric W. "Right Triangle." From MathWorld--A Wolfram Web Resource. Right Triangle.

Weisstein, Eric W. "Altitude." From MathWorld--A Wolfram Web Resource. Altitude.

Cite this content, page or calculator as:

Furey, Edward "Right Triangles Calculator"; from http://www.calculatorsoup.com - Online Calculator Resource.