1766

Prove the red shape is a rhombus.

1610

Prove the red shape is a rhombus.

1520

Prove the red shape is a rhombus.

1336

Prove the rhombus and isosceles trapezoid have the same area iff the their acute angles are congruent.

1227

The blue shape is a rhombus. Prove the red shape is a square.

1212

The blue shape is a rhombus. The green point is the centroid of the green triangle. Prove the red and green points are collinear.

1164

Prove the area of the red rhombus is $\dfrac{8a^3b^3}{(a^2+b^2)^2}$.

887

Given a rhombus. Prove the sum of the red line segments equals the sum of the blue line segments.

703

The green shape is a rhombus. Prove $\dfrac{1}{a}+\dfrac{1}{b}=\dfrac{1}{c}$.

527

Given a rhombus. Prove the red lines are parallel.

505

Find $x$.

382

Prove $a^2+b^2=c^2$.

187

Given a rhombus. Prove the red points are collinear.

168

Given a rhombus. Prove the red line is tangent to the circle.

136

Prove the ratio of the green area to the rhombus area is $\dfrac{a}{2(a+b)}$.

95

Prove all rhombuses inscribed in a given rectangle are similar.

82

Given a rhombus. Prove if any angle of the green triangle is $60^\circ$, then it is equilateral.

63

Given a rhombus. Prove $\sqrt{a+b+R}=\sqrt{a}+\sqrt{b}+\sqrt{r}$.