حاسبة المثلث القائم: الوتر والأضلاع والزوايا

احسب الوتر والضلع المجهول والزاويتين الحادتين والمساحة والمحيط من قيمتين باستخدام نظرية فيثاغورس والنسب المثلثية.

آخر تحديث أمثلة تم التحقق منها: 6

جرّب
المساحة
cm²
المساحة: 6 cm²
الحد الأقصى للمنازل العشرية: 4؛ إلى الأقرب، وعند التعادل بعيدًا عن الصفر
Leg a
3cm
Leg b
4cm
Hypotenuse c
5cm
Angle α
36.8699°
Angle β
53.1301°
المحيط
12cm
Height onto the hypotenuse
2.4cm
Inradius
1cm
Circumradius
2.5cm

Legs of 3 and 4 cm meet at the right angle; the hypotenuse is 5 cm, the acute angles are 36.8699° and 53.1301°, and the triangle encloses 6 cm².

Right triangle, to scale

b = 4 cmc = 5 cma = 3 cmα = 36.87°β = 53.13°
طريقة الحساب S
  1. Hypotenuse (Pythagoras)

    c=a2+b2=32+42=5 cmc = \sqrt{a^2 + b^2} = \sqrt{3^2 + 4^2} = 5\,\text{cm}
  2. Angle α

    α=arctan⁡ab=arctan⁡34=36.869898∘\alpha = \arctan\frac{a}{b} = \arctan\frac{3}{4} = 36.869898^\circ
  3. Area and perimeter

    Area=12ab=12×3×4=6 cm2,P=a+b+c=12 cm\text{Area} = \tfrac{1}{2}ab = \tfrac{1}{2} \times 3 \times 4 = 6\,\text{cm}^{2},\qquad P = a + b + c = 12\,\text{cm}
  4. Height onto the hypotenuse, inradius, circumradius

    h=abc=2.4 cm,r=a+b−c2=1 cm,R=c2=2.5 cmh = \frac{ab}{c} = 2.4\,\text{cm},\quad r = \frac{a + b - c}{2} = 1\,\text{cm},\quad R = \frac{c}{2} = 2.5\,\text{cm}

    The circumcentre of a right triangle is the midpoint of its hypotenuse.

حول حاسبة المثلث القائم: الوتر والأضلاع والزوايا

A right triangle is fixed by any two of its parts as long as one of them is a side. With both legs known, Pythagoras' theorem gives the hypotenuse c = √(a² + b²). With a side and an acute angle, the rest follows from sin α = a/c, cos α = b/c and tan α = a/b, and the two acute angles always add up to 90°.

The default legs of 3 cm and 4 cm make the 3-4-5 triangle: hypotenuse 5 cm, area 6 cm², perimeter 12 cm and angles of 36.8699° and 53.1301°. Builders use that ratio to square a corner, since marks 3 m and 4 m from it along two walls should be exactly 5 m apart. The results also include the height onto the hypotenuse (ab/c), the inradius ((a + b − c)/2) and the circumradius (c/2).

Angle α is opposite leg a and β is opposite leg b. Angles can be typed in degrees, radians, gradians or turns and must lie strictly between 0° and 90°.

أمثلة محلولة

Legs 3 and 4

I know
Both legs (a and b)
Leg a (opposite α)
3 cm
Leg b (opposite β)
4 cm
وحدة النتائج
سنتيمتر (⁨cm⁩)
Hypotenuse c
5 cm
المساحة
6 cm²
Angle α
36.869898 °
Angle β
53.130102 °
Height onto the hypotenuse
2.4 cm
Inradius
1 cm
Circumradius
2.5 cm
المحيط
12 cm

مصدر التحقق: ⁨3-4-5 triple; h = 3·4/5; r = (3 + 4 − 5)/2; Python 3.8 math: degrees(atan(3/4))⁩

Leg 5 and hypotenuse 13

I know
Leg a and hypotenuse c
Leg a (opposite α)
5 cm
Hypotenuse c
13 cm
وحدة النتائج
سنتيمتر (⁨cm⁩)
Leg b
12 cm
المساحة
30 cm²
المحيط
30 cm
Angle α
22.619865 °

مصدر التحقق: ⁨5-12-13 triple; Python 3.8 math: degrees(asin(5/13))⁩

30-60-90 from hypotenuse 10 and α = 30°

I know
Hypotenuse c and angle α
Hypotenuse c
10 cm
Angle α
30 °
وحدة النتائج
سنتيمتر (⁨cm⁩)
Leg a
5 cm
Leg b
8.660254 cm
Angle β
60 °
المساحة
21.650635 cm²

مصدر التحقق: ⁨Side opposite 30° is half the hypotenuse; Python 3.8 math: 10*cos(radians(30)), 25*sqrt(3)/2⁩

45° angle gives equal legs (edge case)

I know
Leg a and angle α
Leg a (opposite α)
7 cm
Angle α
45 °
وحدة النتائج
سنتيمتر (⁨cm⁩)
Leg b
7 cm
Hypotenuse c
9.899495 cm
المساحة
24.5 cm²
Angle β
45 °

مصدر التحقق: ⁨tan 45° = 1 so b = a; Python 3.8 math: 7*sqrt(2)⁩

الأسئلة

How do you find the hypotenuse of a right triangle?

Square both legs, add them and take the square root: c = √(a² + b²). Legs of 3 and 4 give √25 = 5, and legs of 6 in and 8 in give 10 in. If you know one leg and the angle opposite it instead, divide by the sine: c = a / sin α, so a 5 cm leg opposite 30° means a 10 cm hypotenuse.

How do you find a missing side of a right triangle?

For a missing leg, subtract the squares: b = √(c² − a²). A hypotenuse of 13 and a leg of 5 give √(169 − 25) = 12. The hypotenuse must be longer than either leg, or no right triangle exists. With one side and an angle, use SOHCAHTOA: opposite = hypotenuse × sin α and adjacent = hypotenuse × cos α.

What are the side ratios of a 30-60-90 and a 45-45-90 triangle?

A 30-60-90 triangle has sides in the ratio 1 : √3 : 2, so the side opposite 30° is half the hypotenuse; a hypotenuse of 10 gives legs of 5 and 8.6603. A 45-45-90 triangle has equal legs and a hypotenuse √2 ≈ 1.4142 times a leg, so legs of 7 give a hypotenuse of 9.8995.

What does SOHCAHTOA mean?

It is a memory aid for the three trigonometric ratios in a right triangle: sine = opposite/hypotenuse, cosine = adjacent/hypotenuse, tangent = opposite/adjacent. In the 3-4-5 triangle, the angle opposite the side of 3 has sin = 0.6, cos = 0.8 and tan = 0.75, and each inverse function returns the same 36.87°.

How do you check a corner is square with the 3-4-5 rule?

Mark 3 units along one side and 4 along the other, measured from the corner; the diagonal between the marks is exactly 5 when the angle is 90°. A longer diagonal means the angle is too wide: 5.05 m on 3 m and 4 m legs is 91.2°, and 4.95 m is 88.8°. Multiples such as 6-8-10 or 9-12-15 give a more precise check on large slabs.

ما مدى دقة «⁨حاسبة المثلث القائم: الوتر والأضلاع والزوايا⁩»؟

تعتمد الدقة على مدخلاتك وافتراضات الطريقة. يستخدم الحساب العشري 50 رقمًا معنويًا، لكن التقديرات والأساليب العددية وبيانات المصدر قد تكون أقل دقة؛ تقريب القيم المعروضة لا يزيل هذه الحدود. أمثلة محلولة جرى التحقق منها بمصادر مستقلة: 6. مثلًا، يجري التحقق من «⁨Legs 3 and 4⁩» بالرجوع إلى ⁨3-4-5 triple; h = 3·4/5; r = (3 + 4 − 5)/2; Python 3.8 math: degrees(atan(3/4))⁩.

ما مصدر هذه الطريقة؟

Euclid, Elements, Book I, Proposition 47 (Pythagorean theorem); OpenStax Precalculus 2e, §5.4 Right Triangle Trigonometry.

حول هذه الحاسبة

a2+b2=c2,sin⁡α=ac,cos⁡α=bc,tan⁡α=ab,α+β=90∘a^2 + b^2 = c^2,\quad \sin\alpha = \frac{a}{c},\quad \cos\alpha = \frac{b}{c},\quad \tan\alpha = \frac{a}{b},\quad \alpha + \beta = 90^\circ

المصادر

  1. Euclid, Elements, Book I, Proposition 47 (Pythagorean theorem)
  2. OpenStax Precalculus 2e, §5.4 Right Triangle Trigonometry

تم التحقق بالرجوع إلى المصادر

تتضمن هذه الحاسبة أمثلة محلولة بإجابات من مصادر مستقلة، وعددها 6. تُشغّل ضمن مجموعة الاختبارات، ويمكنك تشغيلها هنا أيضًا.

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