Gravitational Potential Energy of an object, relative to the ground =
(mass) x (acceleration of gravity) x (height above the ground)
73.5 J = (0.15 kg) x (9.8 m/s²) x (height above the ground).
1 J = 1 kg · m² / s²
73.5 kg·m²/s² = (0.15 kg) · (9.8 m/s²) · (height)
Divide each side by (0.15 kg):
(73.5 kg·m² / (0.15 kg·s²) = (9.8 m/s²) · (height)
Divide each side by (9.8 m/s²):
(73.5 kg·m²·s²) / (0.15 kg·s² · 9.8 m) = (height)
After doing all the arithmetic on the left side:
(73.5) / (0.15 · 9.8) (m) = height
50 (m) = height