Size It Up

ALL ANSWERS · DINOSAURS · DAILY No. 17 · SEPTEMBER 20, 2026

Size It Up Dinosaurs answer: September 20

The five Dinosaurs silhouettes for September 20, with the true sizes. If you have not played yet, this page is a spoiler — play these five first, then come back to argue with the numbers.

Day 17 ran from a psittacosaurus (2 m) to a tyrannosaurus rex (12 m). The widest gap was round 2, Psittacosaurus against Tyrannosaurus rex, at 6.0×; the closest call was round 1, Deinocheirus against Maiasaura, only 1.1× apart — the kind of round that separates a 90 from a 60.

  1. ROUND 1

    Deinocheirus Deinocheirus mirificus vs Maiasaura Maiasaura peeblesorum

    Maiasaura · reference · 9 m
    Deinocheirus · true length · 10 m

    1.1× longer than the maiasaura

    Deinocheirus is represented here by a selected estimated total length of 10 m. Dinosaur reconstructions vary; this is the published estimate used for this comparison.

  2. ROUND 2

    Psittacosaurus Psittacosaurus mongoliensis vs Tyrannosaurus rex Tyrannosaurus rex

    Tyrannosaurus rex · reference · 12 m
    Psittacosaurus · true length · 2 m

    6.0× shorter than the tyrannosaurus rex

    Psittacosaurus is represented here by a selected estimated total length of 2 m. Dinosaur reconstructions vary; this is the source value used for this comparison.

  3. ROUND 3

    Therizinosaurus Therizinosaurus cheloniformis vs Acrocanthosaurus Acrocanthosaurus atokensis

    Acrocanthosaurus · reference · 12 m
    Therizinosaurus · true length · 10 m

    1.2× shorter than the acrocanthosaurus

    Therizinosaurus is represented here by a selected estimated total length of 10 m. Dinosaur reconstructions vary; this is the source value used for this comparison.

  4. ROUND 4

    Chasmosaurus Chasmosaurus belli vs Ceratosaurus Ceratosaurus nasicornis

    Ceratosaurus · reference · 7 m
    Chasmosaurus · true length · 5 m

    1.4× shorter than the ceratosaurus

    Chasmosaurus is represented here by a selected estimated total length of 5 m. Dinosaur reconstructions vary; this is the published estimate used for this comparison.

  5. ROUND 5

    Australovenator Australovenator wintonensis vs Lufengosaurus Lufengosaurus

    Lufengosaurus · reference · 6 m
    Australovenator · true length · 5 m

    1.2× shorter than the lufengosaurus

    Australovenator is represented here by a selected estimated total length of 5 m. Dinosaur reconstructions vary; this is the published estimate used for this comparison.

Beat these tomorrow

Every round is worth up to 100 points: within 6% of the true size scores 100, half or double scores 45, five times off scores zero. The daily puzzle is the same five for everyone and refreshes at midnight in your time zone; if you want more than five, Size It Up Unlimited draws fresh pairs from the whole library for as long as you like.

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