Hominid Footprints from Laetoli

Thesefootprints, embedded now in volcanic rock, were made 3.5-3.7 million years ago at Laetoli in Tanzania.

They were discovered by Mary Leakey and her colleagues in 1978/79, and provide incontrovertible evidence of early hominid bipedalism.

Note the presence of a human-like big toe and an arch (or instep) under the inner edge of each foot.

Foot length is a remarkably constant proportion of body height in modern humans. In women, foot length is (on average) about 14.75% of height, in men 15%.

From this image, (with its cm scale),estimate the height of the two individuals who made these prints.

• What assumptions underlie this process of estimation?