2166

Prove the blue and red angles are supplementary and $a:b = c^2:d^2$.

1949

Prove $\dfrac{CO}{PO} = \dfrac{a+b}{c}$.

1834

Prove $a':a = p:2R$.

1747

Given $ab = cd$. Prove the red line segments are congruent.

1702

The yellow triangle is isosceles. Prove $a:b = c:d$.

1659

The yellow arc is a semicircle. Prove $a:b = \phi$.

1651

Prove $a:b=1:3$.

1514

Prove $a:b=c:d$.

1495

Prove $m^2:n^2 = ac:bd$.

1487

The red line bisects each green line segment. Prove $PA:PB = a:b$.

1479

Prove $\dfrac{m}{n}-\dfrac{n}{p}=1$ and $\dfrac{1}{m}+\dfrac{1}{n+p}=\dfrac{1}{n}$.

1473

Prove $b:c = (n-1):2$.

1467

Prove $m:n = (a+b):c$.

1368

Prove $\dfrac{a}{b}-\dfrac{c}{d}=1$.

1367

Prove $\dfrac{a}{b}-\dfrac{c}{d}=1$.

1264

Prove $a:b=r:s$.

1222

Prove $a^2:b^2=c:d$

1219

Prove $a:c=r:d$.

1218

Prove $a:b=r:s$.

1163

Prove $a^2:b = c^2:d$.